Yeah it sounds better with the WCR Darkburst pickups although the Fillmores are a bit hotter and I probably should have gotten them instead. Ah well, the Darkbursts kick major ass IMO! That bridge is actually a PRS McCarty Adjustable tailpiece... the stock tailpiece is a cheap POS whereas the REAL bridge like the US PRS bridge I have on there now is totally kickass. I also have TonePros locking studs on the bridge which helps the sustain a bit and a graphite nut, but that bridge is fantastic compared to the stock one!
I'm in the process of upgrading my Tremonti SE now too... I'll take some pictures of that one soon. Right now the Tremonti has US PRS Phase II locking tuners and that same McCarty Adjustable tailpiece (someone actually bought the stock tailpiece for like $15-20! lol) and it needs TonePros studs and a new nut. I think I will be taking the Tremonti to my tech and have him install a Tusq nut (they come with PLASTIC nuts stock... ick!) as well as set it up for Drop-C with .011's. I want to do it myself but I haven't had enough time to take care of it properly. I will however be replacing the current pickups (D-Sonic and Air Norton) with a set of custom-wound Manlius pickups that were originally spec'ed to go into my Thorn. I have since bought a set of BareKnuckle Rebel Yell pickups for the Thorn so I might as well keep the custom pickups and sell the Dimarzios! I'm also going to install two Hovland capacitors from RS Guitarworks so that the tone pots actually DO something!