You may need to search for some images for guidance.
Also consider if intake manifold spacer is used (= moving the intake out therefore closer to the upper rad hose). I did my intake for methanol port injection a while ago and the placement in #1 runner is close to the upper hose. Also watch out for fuel rail clearance, stock 03-05 rails offer most room, S3 rail and Boomba hang over a bigger part of the intake runner......not sure out other rails. I'm using a Boomba intake spacer and a Rage-Tek thermostat housing spacer so that things are more workable.
I'll get an image up in a little bit as it may help a little.
IMO what ever you do, do not drill without mocking up and then double checking things with everything installed in the car....also check the charts so that you use the correct drill bit for the correct tap being used = more important to do this with aluminum then with steel, a badly sized drill and then tap procedure will equal chewed up/galled threads made by the tap (also make sure to use a fresh tap with a little oil for lube)
Heres two images showing original setup with stock rail
When you mock things up have the rad hose and everything else installed.........with everything installed it gets tight, I wound up getting the spacer for the thermostat from Nemo because the one jet is very close to the rad hose with the Boomba intake spacer installed. I bought a Boomba rail and its tighter again because its double the size of the stock rail but I do not have an image of that yet setup yet.
Heres the same thing with the S3 rail
You can better see things here with regards to the rad hose and you can get an idea that the Boomba rail takes up room kinda of like the S3 rail. With the S3 rail both cyl 1 & 2 need clearance
