Klik, the Germans removed the original Russian 76.2mm gun and replaced it with a 7.5cm L/48 gun as seen on Pz IV Ausf G (and later). They also fitted a standard Pz III/IV split-hatch cupola to the turret roof, added a jerry can rack to the fender along with a large tool box. Other than that, it's a standard KV-1 with a cast turret and hull.
Will, ordinarily the wait wouldn't be a big deal but since I had the time off, figured I'd make the most of it considering how little time I got at a stretch on my last project. 
Tread, have to agree with you about the Trumpy KVs although this one was the last one they produced in the series and you can tell that the molds were starting to show their age a bit. Lot of flash to watch out for here and there and some of the mold seams were more prominent. I built one of their KV-1s with the welded turret a long time back so knew what to expect.
Bish, thanks! Virtually anything Allied/Soviet that the Germans got their hands on they converted to some use if they could, even if it was just use it until it broke down or ran out of ammo/gas! They especially liked using T34s for rear area security/partisan duty on the Eastern Front for example. The KV-1s didn't often get captured intact as it usually took an 88 to knock them out so they aren't as well known in German service as there weren't that many that underwent the conversion (exact figures aren't known) that this kit depicts.