the 3" will be fine with this motor... u'll lose a bit in tq but it's a Honda it already doesn't have tq... but u will gain sum hp up top...
the Si in the above video has 2 resonators on it... not sure if he has it on that video but i know when he was done he had the 3" w/2 resonators... it was still pretty loud...
if u had an SRT-4 and didn't have problems with it then u shouldn't ever have a problem with this one... the car literally sounds close to stock until u go WOT... then the beast wakes up...