A couple of tanker companies out here use 'em. I'm thinking they must either last longer,cost less per set,handle better or be cheaper/easier to repair and maintain-can't think of too many reasons to use 'em. As near as I can remember,those wheel adapters are about 800.00 per pair,the wheels will be another 5-600.00 a pair,and I don't know what the tires will run,but it's likely to cost a bit to get the set up you want. It'll sure look awesome when it's done though.
Speed