The electronise speedos fit quite nicely, and there's plenty of room for the 4QD's if I choose to swap over. I've run it up at 12v and 24v, and it sounds a helluva lot better at 24v. The motors are cheap 12v jobbies, so overvolting them to 24v may get them warm. The other decision is what batteries to run them on. I have a couple of 12v NiCad packs i made about 3 years ago... but they are only around 1400mAh.
I am tempted to buy a couple of 8.4v sub C 1900mAh battery packs from technobots, and see how it performs at about 16v. It's just a cse of how h=long the packs last really.
There's enough room in there for 4 packs, so that would be 3800mAh. The big bot used to get by on 15Ah, so just 12kg shoukld be ok on 3Ah?
I've drilled the hubs, and just need to weld them up now.