well,
i have 2.2L

stock exh piping was 1.75"

i now have custom mandrel bent 2.25 meinike style... and DTM ebay muffler

it's unresonated,

the performance gains were much more than i had expected

w/ my 4eat, if i'm cruisin at say 25, and the car is in 3rd, and i slam the pedal down... it shifts into 1st and the tires break free for a chirp...

never ever did that b4, not even on wet roads...

so whoever said there's no gains on NA for exhaust is crazy, cause i experienced pretty strong gains,