so here's the dealio..

my cousin has a pretty decent 3" magnaflow he cut off his old gmc sierra, and my Toyota's 4runner exhaust is a 2-1/2" pipe

so its a single 3" in, and a dual 3" out, and currently just has two turn-downs welded to the outlets, which is fine for now.

I guess my question is from a performance standpoint, will it do anything? I live in California so it would be after the final catalytic converter and o2 sensor, and ive been told that basically whatever you do after a catalytic converter doesn't do much to performance. because fuck California...

but would a 3" be okay to put on the end of a 2-1/2" or is that size difference gonna give my 4runner issues?

I used to have a 2-1/2" flowmaster on my Toyota 4-banger, and that had a 1-3/4" pipe after the catalytic converter, and it ran just fine, but that had WAY less electronics than my 4runner...

no one but chp care about smog. Ive always ran catless in all my cars

better hope you never run into a d.o.t. officer lol

d.o.t. too busy hassling truck drivers over stupid bullshit

hey bro you didn't update your log book enough for me. shut down for 24 hours sir!

trust me, you go by with a buzz bomb of an exhaust and they arnt already with a truck driver, they will pull you over

at least here.

Won't this just make it sound absolutely awful when driving?
Not sure any performance gain would be worth listening to a bad exhaust sound.

bingo

never heard of a dot officer lol.