uhmw? plastic, heated and formed with a good curve on the sides....
quiet, slides good, and way stronger/stiffer than aluminum, bends back after being hit, and since its home made you add a flap to help protect the linkage.....
cheap too
whatever you use make sure its bolted down properly, those hooks or a bar that clamps the frame aint gonna cut it if u actually ride.
what works good is to have someone weld 3 or 4 tabs on the inside frame rails HALFWAY UP so if a rock hits the skidplate and flexes it dosent bend the tabs, also make sure the mounting bolts are as short as possible, if there too long and you hit something the bolt might push up and make marks in the engine cases
heres the only pic i have of it, its only held on with 3 tapered allen bolts, counter sunk, no washers, and its solid, got 4 tabs welded on and didnt notice a tab got put right where the oil drain hole is
ps eline carbon/kevlar (its just fiber glass) is junk
the 450 will have less power and will be harder to start, and will be heavier, but to make up for it it will require more maintenance.
4stroke=dead fish