i would do it where the second cat is...remove that cat and do a dump pipe" electronic so i can swithc it if i need to race or want ot make some noise. i saw qtp had some for about 200, i will probably do somehting like this soon
my friend has the dump on his audi a4 and yeah you do get more boost from it but not that much maybe .5 to 1 psi. cause another kid has it on his jetta GLI and its chipped all it did for him is hold boost better throughout the gears cause his limp mode is 23psi
and he probably turned the boost up which caused it to spike even higher than normal. my car spiked at 20.5 psi and i did not turn the boost up. if i would turn the boost a few psi higher, the boost would spike 23-25 which would pop the motor easily without a tune