we decided to use a s-280 shelter on our truck. At some point we will post a full build thread here but you can find more photos on our instagram @overlandpeanut
We average around 9 with 55psi if the ctis system inflates the tires and will get close to 11 with the tires manually inflated to 95 in the rears and 90 upfront.
Depends on the model and if its been regeared, our truck does 58mph tops stock, regeared it would do around 72-75.... 58 is plenty fast in a 17,000lbs truck.