Ok veterans,chime in on this...
After seeing all the noobies asking advice on their 1st upgrades I have decided to post this basic guide.
*Read this before you even attempt to post on this forum*:
http://albinoblacksheep.com/flash/posting.php
First section deals with upgrades/parts/cost.
----------------------------------------------------
The second section give some basic theory behind "tuning" you SRT.
I decided to use this excellent thread instead of the old tuning thread:
HOW TO: (Explained Upgrade path)
Listed are some very basic guidelines for more power.
The srt-4 engine can handle approx 400hp/400wtrq on stock block and internals. After that internals will need to be upgraded. The stock cams are very good, but if you go big turbo or want to max out a S3 set up you may want to change the cams to a different profile.
IF YOU PLAN ON GOING OVER
350 whp ON YOUR SRT YOU MUST REMOVE THE BALANCE SHAFT ASSEMBLY OR AT LEAST THE BALANCE SHAFT CHAIN, search this topic for more info.
*EDIT* I would also recommend replacing you connecting rod bolts with
ARP brand connecting rod bolts (~$120) if you are going to this level of hp and it is
cheap insurance against a spun bearing. They can be replaced on the car with the oil pan dropped after you remove the balance shaft assembly. You can simply swap them out on the car. This sounds complex but it is relatively easy.
I'm listing 3 versions of upgrades ...
AFTERMARKET SCHOOL OF THOUGHT :
For those that like to "tune" their SRT for max hp/$$$.Can use mods to build up more power. Can be tricky, may need constant tweaking.I recommend Darrell Cox Race parts. DCR part are the best and you get what you pay for.You can order from DCR directly. RealTune is a DCR distributor and has excellent customer service.Also Rage-Tek is an excellent vendor . PtPerformance also has excellent customer service and carries a ton of innovative new SRT-4 parts.
MOPAR (DALE SEELEY) SCHOOL OF THOUGHT :
For those that like to bolt on parts from Mother Mopar and/or just want to bolt on hp and go. Extra $$$ is worth it for total driveability, plug-n-play convenience and reliability/durability.
NITROUS SCHOOL OF THOUGHT
Best $$$/per-HP ratio.Can be used in conjunction and compliment the above schools of thought.
MUST tuned and set up PROPERLY.
I personally recommend dynotune.org. They have awesome N20 kits/accesories at a healthy discount!!!
CAN be a very safe and reliable IF TUNED and set up PROPERLY,but remember mistakes with N20 are costly 
.
DO NOT EVEN CONSIDER A DRY KIT ON A TURBO CAR!!!
If you are unwilling to put in the time/research/setup/$$$ skip this.....
Noobies
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SEARCH these terms if you are confused ----
First upgrades that are MUST haves for any SRT-4.These mods should be preformed before you consider any power add ons.
Catch can for the PCV system:
Check with the many vendors on this site, tons of models available, but I recommend the B.Woody catch can. I have had about 5 different ones and his seems to be the best because it is the most leak proof design and it is relatively inexpensive.
Check valve for the PCV system:
B.Woody and PtPefomance (both vendors on this forum), sell these check valves, they should be installed beteween the throttle body and the catch can.
Check for boost leaks!
Tighten all of the hose clamp on every part of the turbo inlet system. I would highlt recommed replacing the old fashioned "worm-screw" clamps with a set of heavy-duty "T-bolt" clamps complete sets of these are available from a ton of the vendors on these forums or they can be sourced from your local NAPA parts store.
You need to zip-tie every single vaccuum/boostline on the car! Go to your local car parts or hardware store and pick up a big bag of these in multiple sizes.Also, I would recommend a good old fashioned hose clamp or even a fuel injection hose clamp on the brake servo/booster vacuum inlet.If this brake servo booster vacuum line pops off during a power shift you will have near zero ability to push down the brake pedal effectively.
Aftermarket spark plug wires:
MSD,Crane,Magnecore~$50-$75, try the vendors section.
Fuel pump rewire mod:
The factory wiring to the fuel pump just suck because of the high gauge wire used. I recommend at least 10g wire be used and that you pick up a BOSCH brand "fog lamp" relay.
Check here:
HOW-TO: Fuel Pump Rewire
Remove the restriction out of the stock charge pipe
I would also recommend this thread for a cheap fix, ~$35.
How-To: Modify Stock Charge Pipe
Short Throw Thifter (STS)
Mopar or aftermarket and urethane shifter bushings ~$120-$400
Motor Mounts :
Motor mounts (solid filled urethane,urethane inserts, dog bones,Boomba's,etc.) keeps your wheels from "hopping" in a launch and help you avoid breaking important things like oil pans, motor mount bolts and axels.
Fill all 3 motor mounts mounts with liquid urethane (80a), $30.This is a cheap mod that works great for little $$$. Filling your mounts will
vastly reduce wheel hop.
order it here:
http://www.mcmaster.com/
part # 8644K11
Traction bars -OR- Solid Lower Control Arm Bushings:
A number of vendors on this forum sell traction bar set ups or LCA bushing kits.
These kits help eliminate almost all "wheel hop".
Traction bars are great for a car that will be run on the street the majority of the time. They are a simple bolt on set up and will incur a minimmum of road noise.
Solid LCA bushings are the ultimate mod for eliminating "wheel hop", gaining max traction, max road feel and cornering stability. The DOWNSIDE of this, is that you will have a
much more complex install, a
lot of road noise compared to stock bushings and you will need to rebuild them every ~40k miles. I have them installed on my SRT and love them.
First upgrades for more power
AFTERMARKET SCHOOL OF THOUGHT :
240+hp-275+hp range
Stage 1 mopar upgrade $399 =+10-15hp
Spark plugs:
NGK plug#
LZTR5AIX-1 (1 range colder than stock,.40-.45 gap,copper plug),
IRIDIUM PLUGS, BELOW ,pre-gapped to .35
(require aftermarket wires and or a special socket from sparkplugs.com)
LTR5IX-11 - stock heat range
LTR6IX-11 - one step colder
Exhaust
-cat back ~$300-$750 =+7-12hp
-downpipe (cat-less) ~$149-$250 +10-15hp
-downpipe (high flow cat) ~$149-$350 =+7-12hp
-full turbo-back exhuast (cat-less) ~$350-$1050 =+12-25hp
-full turbo-back exhuast (high flow cat) ~$450-$1100 =+12-25hp
Waste gate actuator (WGA) ~$149-$200=+12-25hp
Manual boost controller (MBC)~$30-$250=+12-25hp
OR
Electronic boost controller (EBC) ~$250-$650=+12-25hp
Intake ~$149-$350 =+1-12hp
OR
K&N air filter(stock air box) ~$30-$75 =+1-5hp
MOPAR SCHOOL OF THOUGHT :
240+hp-255+hp range
Stage 1 mopar turbo upgrade $399 =+10-15hp
Exhaust Mopar cat back ~$300-$350 =+7-12hp
Mopar air filter~$35 =+1-5hp
NITROUS SCHOOL OF THOUGHT:
*GET A WIDE BAND O2 SENSOR IF YOU WANT TO USE N2O*
Basic "wet"EFI kit:
(NX,NOS,ZEX,DYNOTUNE,etc.)~$350-$650 =+30-80hp
REQUIRED SAFTEY ITEMS:
Fuel pressure saftey switch ~$40
N2O pressure gauge,mechanical, on bottle ~$20-250
MSD RPM window switch~$90
Air/Fuel ratio saftey lean out switch~$80
Saftey"Blow Down" tube ~$25-$40
RECOMMENDED bolt on addtional parts:
Spark plugs:
NGK plug#LZTR5AIX-1 (1 range colder than stock,.30-.35 gap)
IRIDIUM PLUGS, BELOW ,pre-gapped to .35
(require aftermarket wires and or a special socket from sparkplugs.com)
LTR7IX-11 - two steps colder
Wahlbro 255 lph fuel pump ~$99-120
Exhaust
-3" O2 sensor housing~$150-$180 +7-12hp
-cat back ~$300-$750 =+7-12hp
-downpipe (cat-less) ~$149-$250 +10-15hp
-downpipe (high flow cat) ~$149-$350 =+7-12hp
-full turbo-back exhuast (cat-less) ~$350-$1050 =+12-25hp
-full turbo-back exhuast (high flow cat) ~$450-$1100 =+12-25hp
RECOMMENDED N20 ACCESORIES
Aftermarket ignition,MSD#6211,or #6212 ~$318-$499
Bottle heater~$50-$150
Purge kit~$99-350
Remote bottle opener~$129-$300
N2O pressure gauge,electrical,dash mount~$150-$250
Second upgrades for more power
AFTERMARKET SCHOOL OF THOUGHT :
275+hp-300+hp range
First upgrades (as above)+
NGK plug#LZTR5AIX-1 (1 range colder than stock,.35-.40 gap)
IRIDIUM PLUGS, BELOW ,pre-gapped to .35
(require aftermarket wires and or a special socket from sparkplugs.com)
LTR5IX-11 - stock heat range
LTR6IX-11 - one step colder
Larger front mount intercooler -FMIC-
(Direct fit intercooler recommended if you are running a stock turbo or a S3 turbo)
~$350-$1050 +10-20hp
60-55mm throttle body ~$250 +5-10hp
True 60mm throttle body+60mm spacer ~$370 +7-15hp
Ported manifold ~$250-$399 +10-20hp
-3" O2 sensor housing~$150-$180 +7-12hp
MOPAR SCHOOL OF THOUGHT :
260+hp-280+hp range
First upgrades (as above)+
Stage 2 mopar turbo upgrade ~$799 (w/o toys)=260 hp
Stage 2 mopar turbo upgrade ~$1299 (w/ toys)=280 hp
IRIDIUM PLUGS, BELOW ,pre-gapped to .35
(require aftermarket wires and or a special socket from sparkplugs.com)
LTR5IX-11 - stock heat range
LTR6IX-11 - one step colder
NITROUS SCHOOL OF THOUGHT:
Direct port "wet"EFI kit:
(NX,NOS,ZEX,DYNOTUNE,etc.)~$750-$1050 =+100-150hp
Saftey upgrades (as above)+
Wahlbro 255 lph fuel pump ~$99-120
Aftermarket ignition,MSD#6211,or #6212 ~$318-$499
Clutch upgrade $650-$1100
Axle upgrade $770+
RECOMMENDED N20 ACCESORIES:
Progressive N20 controller~$350-$750
Third upgrades for more power
AFTERMARKET SCHOOL OF THOUGHT :
300+hp-650+hp range
Second upgrades (as above)+
AEM EMS, TEC3,MEGASQUIRT,MOTENG aftermarket engine computer:
~$500-3500
Large front mount intercooler -FMIC-
(RACE intercooler recommended if you are running a BIG turbo)
~$350-$1050 +20-60hp
BIG TURBO KIT $1550-$4000 =150+hp-450+hp
BRAKE upgrade $650-$1850
Clutch upgrade $650-$1100
Axle upgrade $770+
IRIDIUM PLUGS, BELOW , pre-gapped to .35 - gap as needed -
(require aftermarket wires and or a special socket from sparkplugs.com)
LTR7IX-11 - two steps colder
MOPAR SCHOOL OF THOUGHT :
310+hp-365+hp range
Second upgrades (as above)+
Mopar 2.5" downpipe ~$350
Mopar clutch upgrade ~$550-$600
Stage 3 mopar turbo upgrade ~$3000 (w/o toys)=310 hp
Stage 3 mopar turbo upgrade ~$3599 (w/ toys)=365
hp
IRIDIUM PLUGS, BELOW ,pre-gapped to .35
(require aftermarket wires and or a special socket from sparkplugs.com)
LTR6IX-11 - one step colder ( S3 w/o toys >340 hp)
LTR7IX-11 - two steps colder S3 w/toys <340hp )
NITROUS SCHOOL OF THOUGHT:
Direct port "wet"EFI kit:
(NX,NOS,ZEX,DYNOTUNE,etc.)~$750-$1050 =+170-250+hp
FORGED PISTONS~$450-$750
CRANE N20 SPECIFIC CAMS~$300
Saftey upgrades (as above)+
Progressive N20 controller~$350-$750
*UPDATED*AGAIN*SRT-4 Basic Upgrade Path & Tuning Guide
Linear Mode
