which PI cams give the most noticeable sound/idle?

I had Comp XE270AH cams in my '03 GT. It had a nice lope, ran well, and got me into the 12's. With that said, I would go with VT Stage IIs. If you install the cams "straight up" like many people do and do not degree them, the Comps can cause problems with PTV clearance. I got lucky with mine.

Mine had a nice lope and the Comps have a 112* LSA. I think the VT Stage IIs are ground with a 108* LSA which will give them an even choppier idle. Just remember for these to perform well, you need the gearing to back them up. My Comp 270s were OK with my 3.73s, but really could have used 4.10s or 4.30s to keep them in the sweet part of the powerband at the track.