I am thinking of buying the following:
5 zigen border 304 max cat back
HKS downpipe
Pipe for to replace resinator

Where the pipe to replace to resinator is concerned is this advised and is it known as a decat pipe. I am not really bothered about noise as you can probably guess from have a 5 zigen.

Also would anyone recommend anything that will increase the performance more than a HKS downpipe or anything to improve the whole system

 

THe centre resonator pipe is also called cat bypass pipe because uk turbo has a cat in the centre section. most jdm cars dont, so you can replace this for a straight through centre no problem.