CrossRC 6X6 Help

[Give a Flying Duck]

Hello, Everyone.

Longtime lurker, new poster.

I've lusted after a 6X6 for a long time and now it's finally gonna happen!

I have decided on one of the CrossRC Platforms.

However, I'm having difficulty finding the differences between the following … is there anyone who knows where to find this or even better can shed some proper light?

https://www.crossrc.us/shop/kc-6e-crawler-kit/
https://www.crossrc.us/shop/uc-6/
https://www.crossrc.us/shop/hc-6-kit/
https://www.crossrc.us/shop/mc-6c/

My original intention was the HC-6 as I love the M35 body, but what I really want is the most capable rig out of the lot for possible scale competition.

The platforms appear slightly different in capabilities (and cost, but cost isn't really a factor) and I'd really like a little help.

Thanks everyone!