VR6+T is a very common mod, and there's shitloads of material online about it, plus a wad of aftermarket bits.
The engine itself has been around forever in various configurations - 2.8 12V, 2.8/3.2/3.6 24V. Yes, they're heavy but as mentioned, they've got a lot of meat in the block. 15° angle between bore center-lines, so they run a conventional inline-6 crank and firing order... Add to that the asymmetric port length between cylinders (inlets are on one side of the head, exhausts on the other) and they sound absolutely awesome.
1000hp+ is achievable - Just spend 30 seconds on YouTube looking for VR6 Turbo Mk1 and Mk2 Golf conversions...