Straight-thru perforated Resonator or one with baffles?

I'm running a custom exhaust set up, all the way from the cat-back on my 2001 Acura Integra GS. When I upgraded the pipe from 2" to 2.25", I didn't install a resonator. Now I have this raspy sound everytime I get above a certain RPM, especially under great acceleration. Now I think installing a resonator would eliminate the raspy sound, but what kind do I get? The straight-thru, perforated core resonators or the ones with louvres and chambers? I really want to keep the free-flowing performance the way it is. I really want to get rid of that nasty rasp sound. Can anyone help me with this problem??

Maganaflow Uses Perforated They Say Its More Straight Thru Than Louvres, Which I Think Are Little Scoop. I Have Yet To Here Of Resonators W/ Baffles.