I believe the resounding response, especially being on the forum you are, will be DO IT!!
I have had a RL 4x12 loaded with G12H's, and now currently run through a FL 4x12 loaded with G12K100's. The power and wind that thing generates is off the hook. But more importantly, there's been a complete redesign in the last year or so to Diezel's 4x12's. They definitely did something right because I've run my head through a couple other cabs and nothing sounds as good as the Diezel cab. Personally, I'm pretty happy with the G12K100's being stock in the cab - historically, I've found V30's to be a bit too much in the mids. The G12K's are killer. Further to this, you can also 2x2x12 your cab, making an X pattern of 2 types of speakers - maybe going the V30 and G12K route. Up to you - up to your ears. But as a devout Diezel fan, all I can say is there's something pretty magical about their cabs.
Hope this helps.
V.