Ahh really?well I haven't been pulled over once in the 2 years of owning it which is surprising to be honest haha but how would I go about a external waste gate ?
If your car is stock (ish), you need a new exhaust manifold with wastegate outlet (500+ pounds) + External wastegate (250 pounds) + new turbo OR internal wastegate in stock turbo welded shut (stupid idea) (upwards of 500+ pounds) + Custom piping fabricated so as to not vent directly into engine compartment and therefore the cabin (250 pounds) + new water and oil lines to your new turbo (100 pounds) + New dump pipe (500+ pounds) = over 2 grand
All those prices are estimates as I obviously don't use pounds day to day, but yea, you're looking at a hell of a lot of money for just a screamer pipe, mate.
That popping you're hearing is probably just backfiring. The cars you're hearing doing that aren't tuned quite perfectly (if at all). Up your boost pressure just a tad and you'll run rich down low, viola, popping sound. A screamer pipe literally SCREAMS when you hit max boost. they're effing loud and damn pointless if you're not running massive power figures.
(Feel free to chime in anyone else. I have little to no hands on experience with this stuff, just thought I'd get this out there asap to avoid this thread getting nasty)