I did the silencer upgrade only (as for performance upgrades). I like it alot. Others will debate the PCIII or the Tuneboy. I've seen (heard) some have done both. For what I'm not clear about. From my gathering, I'd go with the Tuneboy for it's capability to eliminate several of the factory faults (including the real performance hinderances). I don't have either (PCIII or TB), mostly because my well ran dry. We're under exceptional drought conditions in the heart of dixie; but at the same time, I really don't feel I need either. Other's exclaim huge performance improvements, then I get excited about more bottom end performance. That feeling subsides as soon as I get on the beast.