I've got the Kakimoto N1 system with a 60mm decat.
It's not the loudest exhaust ever and still passes the strictest trackdays but it's pretty brutal in VTEC
Sounds fairly raspy below 3000rpm, but above that it's absolute heaven

It's not too loud at idle either.
Beautifully made system though.
I'll try and find a pic of it when it was last out on track.