alot of trucks have either procomp, doestech (sp?), or fabtech.
the springtech ones are the doestech spindles which are very simular to procomp spindles. not much difference.
wheels and tires -
15x8s or 15x10s or you can obviously go larger in diameter.
tires you can run 33x12.5 - 35x12.5, 33x12.5x15 are the most common.