He should better use a stock Neon 2.0 exhaust.
Stock SRT is too loud for gemand inspections.
(After that he can swap to an original part and pretend to be clueless... That's what i did.)
Dammit the taillight deal sounds great - but don't you think that you could leave them in the car for the inspections?
Maybe better find a cheap set taillights and give them the buyer if needed - i guess he will be very happy to have the LED lights then.
And he should not be afraid to get in trouble with the aftermarkets then: his registration will say "lights without euro-signs" (something like that).
It will NOT say "stock SRT lights, number blablabla"....
So every light will be okay - and he can be in the happy situation to say "i don't care for TÜV".