[f32458]

This is a nice thread, helps me understand more on our exhaust games. I had iPE F1 catless setup on my E90. It was OMG loud and sounded like a beast. It had bad smell. Unfortunately, I lost torque. I had iPE did a custom job on my x pipe and they said now I have 200 cell cats. The torque improved and the smell stopped. But I am not sure if I have the best design X pipe in E9x M3. What is my X pipe really?
I am thinking to get TP's and a stage 2 tune. Along with my iPE axle back. But I just remember why spend extra money since I have the iPE X pipe sitting there. So probably no TP for me. What do you guys think? Since most of the sound is coming from axle back and the least performance gain from rear axle back, I will install my new iPE axle back since the sound is very good imo. For sure it weights a bit more than Akra but the valve control is a very fine piece.