Kawasaki Mule

I suspect that the parts (or at least some of them) at a dealership are the same as those at a parts store. I have seen chain parts stores delivering parts to dealerships.  What a ripoff!

In my experience with repairs to my vehicles, dealerships and repair shops charge 2x-3x the retial price for parts that I can buy at NAPA's retail price.  My AC compressor $995 from the dealership, $485 fromn NAPA.  I don't buy lifetime warranty parts.  They are exactly the same  as the 90-day warranty parts, just painted a different color.  You're paying about 50% higher price that their lifetime part and they're betting you won't need to replace it.  I've never would have been able to collect on a warranty replacement on anything I've ever purchased.

That's a nice look. You might try wheel spacers to help with the rubbing. 

just call me Zap

It's a common problem with towing, at higher speeds. You take preventive steps, or you take your chances. Personally, I'd probably make a padded plywood overlay.