Hello, newb monte owner here. I've been going through the threads, but could use some clarification. Does my stock downpipe for my 03 monte ss end at 2.5" or 2.25"? I want to delete the ubend, put on 2.5" pipes, and maybeget a diff cat and mufflers. So the question is, should i upgrade the downpipe, or would i be fine leaving it alone? Also, if i left the stock cat and res, would it be ok with the pipe upgrade? Just looking for a little more power, no heavy modding planned for the future.

 

just do 2.5at the end of the cat straight back, welding 2.5 pipe to the end of the cat will also get rid of the ubend. or depending on what the cat looks like inside do a whole bolt in down pipe from zzperformance.comthen get rid of that 4 foot resonator and do like a 18-21inch glasspack into dual flowmaster 40's