The R stock sounded great. I added the Icebox (not the short ram with it yet) and it WAILS.

The reason why the R is louder (other than soundproofing not being there) is the single runner intake manifold. VTEC kicks at 5700 or 5900, depending on throttle position. It's VERY obvious. It actually makes something rattle after the icebox.

The GSRs, you only really hear it after the secondaries open up. Stock, at least.