custom crush bend or mandrel kits

[gojo83]

Here is the question I am looking at the cat back kits and they are fairly priced but I was talking to the local muffler shop and he said he could do a full header back exhaust setup using all magnaflow equipment including a high flow cat from mangaflow and a magnaflow muffler. I read the sticky about pipe size and well I am thinking that a 3 in crush bend setup would probably flow like a mandrel bent 2.5 or should I see if he would do a 2.75 crush bend setup being the most effiecent for the system? I am looking for average hp and torque not super impressive numbers as this is going to be mostly a DD. I am also putting a ram air setup on but I was looking around and mine is a 98 bird and the FIPKII seemed to skip that year thus my question being would a 99 kit fit on the 98. I am also thinking of doing a egr delete. Any advise or opinions on that. One last thing looking around there is posts about an IAT I could not find what that is or what it does. Thanks in advance.