Enclosed Car Trailer Buying Help!

Looking the ad over... upgrade the leaf springs to torsion axles, upgrade the puny 3500lb axles. We went with 5200lb axles on both of our trailers, and on the 28 we went with 16" wheels as their are better trailer tires available. whether you use the trailer or not, you can pretty much count on replacing the tires every two years. The desert just plain beats the crap out of them.... and getting a flat isn't fun. We run 10 ply tires on both of our trailers.