Hello,
I Just put a header and flow through cat on my car last night and it sounds great until it gets to around 4000 RPM, then it sounds like a honda civic ricer. I have had a Megan Racing Cat Back on there for some time now and it sounded amazing through the whole rev range but no wit is ruined in my oppinion. is there a way to deepen the tone of the higher rpm range to "fix" the ricer problem.

Cheers,

 

The lack of catalytic converters mixed with the header is what is giving you the "ricey" sound. You can try adding a resonator, but with the header comes a more raspy tone.

 

Also, the fact that it's a 1.6L SOHC NA 4 Cylinder, has the most to do with it.

Have a custom exhaust made: 2.25" pipe, Vibrant Ultra Quiet Resonator, Vibrant Streetpower offset / offset muffler. That would help. Or ditch the header...