Hey guys, I recently bought an accessport for my 2013 MR. I knew that the car had a tune on it before I connected the ap, but was under the impression that it was only a cobb stage 2. So once I connected the ap, I flashed a stage 2 tune onto the car since I thought it wouldn't change anything. I took the car for a test drive and it drove horribly. The car would behave normally until the turbo kicked in and whenever I shifted. The car would stutter and backfire a ton (I saw about 8 for total knock sum at one point as well), also whenever I hit about 3500 RPM the car would act like it was choking and would lose power. I'm new to tuning and would like all the help I can get, please.