TLDR. You can smoke test the car yourself. Do you smoke cigarettes? ( I'm not kidding ) or you can buy a little smoke machine for like 20-$60s and return it. All you have to do is blow smoke into the air box/intake when the cars on and see where the smoke might be coming out of.
BMW 2006 M5 - REALLY LOUD
Audi S4 2000 Stage 3 - Dat turbo spool
BMW 2000 3-series
Because race car SOLD
Maserati 2004 M128 GT
- HREs/tint/straight piped SOLD
BMW 2006 M3 - stock - SOLD