I'm wanting to get the motordyne xyz w/straight pipe, and I have the berk technology test pipes and magnaflow mufflers. The magnaflows were a gift from my parents when I first got the car. It was stock, and for Christmas they decided to surprise me by bringing me down to the local exhaust shop and having the guy put a "custom" exhaust on. Afterwards I got underneath the car and found that there was nothing custom about it, it just says magnaflow on the muffler with the stock y-pipe. My main concern is diameter of the piping. I was trying to research y-pipes as best as I could before posting and I saw a lot of people talking about inlet/outlet sizing and that if it doesn't properly match up it'll become more restrictive or sound bad. I have no clue what diameter my current exhaust is because I wasn't the one who bought or installed it. I am also getting a muffler delete, so would the exhaust shop just make the piping the proper size for the y-pipe? And would it be okay driving around with that y-pipe and my current mufflers for a few days until I get the muffler delete? I do apologize for the noobish questions, but I tried for the past 45 minutes or so to find answers to my questions but found none.