i would strongly advise aginst shipping stuff fedex.
i work with a guy who has worked for both fedex and ups, from what he says fedex is about as rough on boxes as you can get. wouldnt' matter much for wheels and tires (mounted i'm guessing) but anything else i wouldnt' do it. too many storys of throwing boxes to see if anything breaks, smashign boxes to make them fit, that sort of thing.
ups frowns on that sort of thing, i guess they care a little.