yes. backpressure will be a problem.
And believe me ..

it doesnt sound GOOD!
my friend has a yoshimira motorcycle exhaust muffler bolted onto his crx, and OMFG..it is the most ANNOYING ****ING SOUND ON THIS PLANET!

it is so friggin loud and unbearable i just want to stomp the **** out of his muffler everytime i see it parked.

And by the way.. his crx is running 17's at the track with i/h/e.
So you will see absolutely no power gains from it, nor does it have the potential to build gains wih all of the othr essential bolt ons.

he recently boughta magnaflow catback exhaust system..
I don't know what he's running at the track now.
but im sure he will see bigger gains.

so IMHHO..
DO NOT PUT THAT MUFFLER ON YOUR CAR!
ha.
sell it an save up for a catback.
Apexi N1, or greddy EVO, or maybe a Thermal R&D are really good!

payce