What is a hybrid Tiger?
The last 50+ Tiger I's were "hybrids"; meaning they were stripped down at the factory and rebuilt with new and old parts. 54 recycled hulls and 32 recycled turrets were used.
These Tigers could feature an old hull with new tracks, combined with a Zimmerit-ed old turret with pistol ports, sometimes with a lighter muzzle brake and track links on the turret sides/bow. Or if the Tiger was coming from a driving school, it could have been a early Tiger with late road wheels etc. Overall, they were quite
rough looking vehicles, with patchy Zimmerit, missing road wheels, mud flaps etc.
Panzer Abteilung Kummersdorf/Pz. Div. Müncheberg had at least 5 hybrid Tigers and they participated in the last breakthrough battles from Berlin.
Here's one after the battle, at Lessingstraße - Tiergarten, Berlin:
http://oi60.tinypic.com/xm4ykx.jpgEdit: I'd add more streaking, dust, overall weathering on the '45 vehicle skins (especially the ones with disc camo). If you'll see pictures of the late war vehicles, they were all very grimy and dirty. Basically, the Germans used anything that could shoot and most of the vehicles couldn't even move... it was very Götterdämmerung'ish.