I just came across and some headers don't know the brand and a magnaflow exhaust what size cat and pipe should I use and is it any other sensors other then the o2 on the exhaust system?

 

Refer to the older pipes

 

2 1/2 inches. only o2 sensor

 

Pretty similar guessing you have a f23?
Here's what I did.. I grabbed a stock ap1 s2k catback off craigslist for 40 bucks.

My 93 I was doing the exhaust on today. Stock a6 cast 4-2-1 header. 2.25" collector welded on. From there I used the stock s2k helmholtz resonator into a stock cat (63mm) off a jeep cherokee that I had here. Its in perfectly good shape, can see through it perfectly& is Cali legal still
The stock honda one was 17/8" & I couldn't see light through it.

After the cat I've got stock 63mm s2k piping into a magnaflow 18146 (33" long) resonator its 2.5. Again had it laying here, ment for a jeep hence the 2.5" diameter. From there 2.25 crush bent pipes back to a stock s2k twin loop muffler.


I have no idea how it sounds because my darn car won't start lol. So once I get that figured ill post a video. I'm sure it'll be quite & without rasp. If its too quite I intend to do the "uk mod" that s2k guys do for a little more sound mainly.

 

Thanks for the advice I am going to buy a n1 cat back exhaust cut the n1 muffler off and put the magnaflow muffler on there and use a hi flow magnaflow cat