I didn't run numbers with stock. But with the Borla exhaust on I dynoed the car and only got 283hp at 12/13 psi boost on the best run.
This car has... sport 500 turbos upgraded Z1 ECU Upgraded larger intercoolers 610cc injectors pop charger engine had high compression 6 months ago at over 160. automatic tranny.
Just by feel, I'm assessing that the borlas aren't any better than stock. Or if they are it's not a lot. Could be I have other issues with the car. He may have ran the dyno with the AC on, but he assured me it didn't matter.