I have civic si 2000 with complet magnaflow exhast 2,5'' and muffler 4''

Just got 72 hours this exhaust is legal or ?

What are you Asking?
Is magnaflow legal? Theres millions of people running them on their vehicles, im one with the same set up as you

are you high right now?

must be fast.

Thanks for lulz op.

but on a serious note, take the exhaust off, not cause of the legality, but cause its a ricer and it sounds like a metal spoon stuck in a garbage disposal.

ROFL

here's a fix

put a 300 shot in your trunk run it on a dyno at 9 grand for a few hours

pretty sure 4'' is illegal

That seems way bigger than stock.

It all depends on your state but more stricter states like CA have that as illegal.