Exhaust question
 

So I'm thinking about improving my exhaust system, probably upgrading to a Borla cat-back. Here's the thing: My friend told me that with the stock turbo I'd be losing more back pressure than I'd want and I'd actually lose some performance. That's definitely not cool, lol.

So the question, I guess, is: is he right? Should I leave the stock exhaust alone for now? See my sig for the only mods I've done to the car.