I like your mod, the ball probe and the g probe are perfect and very usefull. I suggest you to break the ATV in 3 parts: a central part (3,75m) with the CPU , an upper part a 3,75 to 1,25 adapter maybe with a light and a lower part 3,75 to 2,5 as engine mount and cargo bay, this will make the ATV parts more flexible and usable in different projects. RU 1m and RU2m are very interesting but I think that they needs a better model they looks too flat now , maybe something like the 2,5 stock decupler.