Still one queston. What do you guys think about the downpipe. Right now my downpipe is 2,5" without precat and main cat. People have said that removing the main cat lowers the power and torque. If that's so how I can get the best benefit from the exhaust side? So I have the 2,5" cat-back and I'm going to make the 4-1 manifold. Only part I'm going to change if needed is the downpipe section. Right now I'm driving with the original downpipe with the precat and main cat and it is very difficult to say if there is more or less torque in the low down rpm range compared to my own 2,5" downpipe. If I need to make a new downpipe I still would like to use 2,5" pipe and put something to it to make the back pressure raise. Do I have to use a cat to raise the pressure or can I use something else?