ZiggenBallz, im not following u 100% man, u asked are u going with a small legal unit or a completely straight thru? do stuff for the overall plan for ur car? well, let me say thanks again to u, and everyone else who has written so far. well, let me answer what i think u may mean, but im probably wrong, my car right now would fail emissions, OEM cat has gone bad.. cost of OEM cat=$1000 including labor. my cars feels like its fallin apart. mechanic told me to change my cat.. due to not changing spark plugs on time, coolant flush that wasnt done... anyway, i am not going turbo or a swap as of yet, so after my cat is put into place, it should be a smog legal car (just changed one of my O2 sensors for $250 also), cuz carsound says i am supposed to be in accordance with gov. spec.(thus passing emissions) i am getting this cat to save money and save my comfortable ride. im not in cali, im east coast, where emissions is a little more flexible. i just have a catback, CAI, and now getting a high flow, thats it. please hit me up, if i've not answered ur question... btw, i am fixing the problem which has initially has hurt my car, so it wont destroy this high flow cat either, and i mean, the overall plan, is to have my car which already has rims, lowered, a kit, looks nice, and some bolt ons, and im assuming i can sell this car eventually with this high flow cat, cuz i pass emissions, i dont want to buy an OEM cat which is expensive.. is that good enuff? is there anything that a high flow cat will present which deter my decision, im not going for speed u have to understand, just to make my car run properly again