i need some advice guys

one of my best friends has a 99 civic si. I need a legal high flow cat and muffler with screw in silencer. what are the better performing brands and what would be your advice?he bought a obx hi flow cat and come to find out there pretty much straight pipes so now his car is in the shop and they wont give him his car back until he buys replacement parts.so i need to find the right parts as soon as possible. please help, thanks guys...

go get a randomtechnology high flow cat