Hello everyone! I just bought my first Subaru about 3 weeks ago (It's a 2011 WRX Sedan) and I have a question about the Stage 1 tune. I haven't done anything to the car besides window tint, but it came with the SPT Catback from the dealership so I am not sure if I need to do anything else before even trying to get a tune. I read on a thread that it could increase the hp/trq by roughly 20/70 respectively. My question is, if I did the Stage 1 tune how much, if at all would that effect my gas mileage?