I was told by one mechanic that the exhast of a 9 civic ex is the same as a 99 civic lx. Installed a new header and highflow cat. Had to weld on. Still no significant power gains. Coiuld it be the stock exhaust holding the performance back? oh yeah my engine is stock to, SOHC 1.6l

u wont feeeel it on a pretty much stock sohc
maybe u would if on a dohc on a good day ecspecially jsut for headers and a cat thats polluting the world

if your going to put a hi flo cat on the stock piping.................you might as well just keep the oe cat on.

if your going to put a hi flo cat on the stock piping.................you might as well just remove your entire exaust.

well said