Geez guys calm down. First of all, the borla has 3.5 tips!!!!!!Not 2.5!!!!! again...the borla has 3.5" tips. I noticed a nice gain in low end torque, and a steady gain throughout the rest of the rpm range. According to tests, the borla is the only exhaust(prefab) which gives noticable gains. There is an article floating around here somewhere about it. i'll try to find it and post it