I wouldn't spend the money just to upgrade to a TRUE. Sure it's a kickass heatsink, but I'd rather put that money towards a WC loop.
I myself run a Q6600 on a TRUE, and while it does a pretty nice job, it does get pretty hot when I'm folding but that's understandable, it's folding...
I don't agree and believe at all what Adrienspawn said.. He wouldn't get the same temps with a $300 WC loop, that's just a dumb thing to say.. You wouldn't see any WC'ers in here if that were "true".. (no pun intended )