IMO Lead 1 red kinda sucks either way. Don't worry which one you get, Lead 1 red is the only affected mode regardless. The original Triaxis and the new Triaxis have somewhat usable Lead 1 Reds, which are closer to a Marshall Super Lead IMO. For those types of sounds though, I prefer Lead 1 Yellow, which has a huge warm tone to it.
Version 2 just means you have continuous MIDI control, so you could theoretically assign each value to a MIDI channel or assign all of them and sweep through a clean to heavy sound with an expression pedal. It's a nice touch but I've never used it.
From what I understand, basically there's 4 versions of the Triaxis:
1. The original
2. Version 2, phat mod - Lead 1 Red is modeled after the rectifier and has what's basically a bass boost many people didn't like
3. Version 2, non-phat mod - Lead 1 Red still has a rectifer style sound and a separate circuit board, but doesn't have the bass boost and sounds a bit better
4. Still V2, I think after 2003 or 2004 they basically said they didn't want to put the second circuit board in there anymore, and while the unit is still V2 and has continuous control, Lead 1 Red is back to the original.
Mine is a 2008 model, and it sounds like the original. Awesome preamp. It can't do the rectifier sound, but when you partner it with a 2:90 and crank it, from personal experience being in the same band with a triple rec, it competes nicely with a rectifier and actually can have just as much bass, while having a 'cleaner' distortion sound. That's totally my opinion and not all will agree with it, but I prefer the Mark amps and Triaxis tones to rectifiers. Personal choice.
Plus, you can play the Triaxis / 2:90 at just about any volume, including bedroom levels, and they sound awesome.
If/When you get the Triaxis, let me know and I'll forward you a bunch of my sounds for it. Honestly you can't go wrong with it unless you totally hate Mesa sounds. I just think it's a phenomenal preamp and you have to try really hard to get it to sound bad.
Oh, and put a Tung Sol in V1 immediately
It adds a lot of punch and clarity, and there will be less noise. Also, the Triaxis is a noisy preamp when cranked, read the instruction manual about how to set the gain levels, and put a nice gate after it in the rack. My G-Force has a gate that works great for it. Roger doesn't like the gate in the G-Force and he'll disagree with me, but I used the G-Force as a gate in rehearsals, live use, and in the studio and I never had any real unwanted noise when it was set properly.