The super single tires on the A1 and A2 are really nice and have a better ride and will off road better then the smaller G177 Goodyear tires. Pro's for the smaller Goodyear's are the fact that they are the same size tires as used by over the road trucks so you can buy a replacement from any truck stop anywhere in the country.
The super single is a unique sized tire, and if your away from home base and need a replacement tire your going to have to order it and wait to take delivery. Another pro of the G177 Goodyear's is they weight about 250 pounds each, so one person can change a tire by themselves, the super singles weight about 500 pounds each and are alot harder to change by yourself, that's were soldier B come's in handy.
Another plus to the smaller tires is when you have to change a flat the G177 Goodyear's lug nuts are torqued to 325 to 350 foot pounds, the super singles lug nuts are torqued to 450 to 500 foot pounds, this is another case were soldier B come's in VERY HANDY.
The difference between the M923 and say a M925 truck is the M925 has a winch and the M923 does not. As other members have pointed out the A1 has the super single tires and the non turbo motor. The A2 has the super single tires along with the turbo motor. Now the non A1 and A2 trucks come with the smaller tires along with the non turbo motor.
My truck has the non turbo Cummin's 250 with the smaller tires and i am able to drive it at 55 MPH at 1900 RPM. Now due to the nature of these trucks i am not so sure i would want to drive it much faster then 55 MPH, but YMMV. I have never owned or driven the turbo equipped A2 model truck so i can offer you not insight on that engine.
Now i know other members who own the turbo trucks and they tell me that the fuel mileage is better in the turbo truck and while driving them they say that the noise level inside the cab is alot less then inside the non turbo truck and they ride nicer on the super singles.
All in all i think you will be happy with whatever model truck you end up buying. One thing i will tell you, try to buy a truck with all the equipment you want already on it. The reason i say this, lets say you buy a truck without a winch and you really wanted one with a winch, it will cost you a few thousand dollars to add that winch later on, so your money ahead buying it with the equipment you want in the first place, then trying to add it on later. That's just my 2 cents YMMV.
