I dont believe the 70 MM TB is available yet, I could be wrong though. I've not read anything from anyone that has one yet. So my opinion would be if it is worth the money and the gain is there, then it might be a mod to consider. Well see.
The location of the the TB with the JRSC does not move if I'm not mistaken.
I have a question for you, well take that back some. Why are you so interested in the information? Are you looking at stepping up into something faster than your ZX2? Such as maybe a SVTF? Just curious.