As far as the gap, I specifically asked Christo about it when I picked it up and he said that was how it needed to be to deal with the flex.
I am sorry for any confusion caused by my typo. The Nittos are 275/70/18, not 275/75/18. The only 75 series tire I could find were not ones I was interested in.
Don't know exactly what the spring rate is- just that they are the Heavy Load 2.5". I'll call Christo later and ask.
Center of hub to wheel well is 21 1/4" front and 22" rear.
I know the tires may not be quite as aggressive as many on Mud, but after doing a lot of research, I made the compromises that I hope will work for me. I considered, in another thread, keeping the brand new Michelin Latitudes that were on it and buying some really aggressive tires on another set of rims but decided against that because I llike having more storage space after getting rid of the extra winter sets for the M5 and X5 and I didn't like the idea of driving long highway distances on a more aggressive tire- noise, handling etc. Even living in Utah, it can still be a long haul to get to where we want to be offroad.
Besides, it's going to be

her daily driver- I get the Lexus. I know it's it's wrong on soooo many levels, but that's the deal. I can live with it as long as I am behind the wheel off the pavement.