Hey Guys! I just bought a 2009 WRX Wagon from Silverline Automotive. I Love everything about the WRX. Recently I noticed a sputtering problem. The car came with a full 3" TBE no resonators or cat. I believe it was an Nvidia. The sound was a bit too loud for me and sometimes it would back fire and smelt like it was running rich. so i had the shop put in a stock exhaust from the cat back. I also had the coil pack replaced. The car doesn't sputter in 1st or 2nd gear but in 3rd gear right before hitting boost it sputters and shakes a little. If I floor it kinda goes away. I'm not sure what is causing the problem? Idk if i need a tune or if the car had a previous tune. I have no check engine lights or anything.. Can anyone help with ideas?