hm.. i just bought a 'high flow' CAT (obx racing).. they are cheap.. less then 100$... usually about 60-70..

i just installed it today, and i can feel the difference... i like it :-P
my old one was worn out anyways..

and you do know you wont pass emissions testing for inspection with a gutted cat or a "racing cat" (aka testpipe/fancy gutted cat)