They don't cover much at all on the 07... mostly just the actual tubing of the a-arm... The 06 and earlier version of the yami a-arm were 10 times more protective... The plastic ones come up higher than the aluminum ones do... If I were you, I'd wait a few months and see if someone else comes out with something that goes higher and protects more...

 

I really never noticed any problem with not sliding well enough with aluminum plates. The problem I had with plastic plates is they break too easy. for the A-arms I cut them as high and wide as I could to protect as much as possible, without them hitting on the up travel of the a-arm.

 

After market skid plating is one of the best items I put on my Grizzly. I ride in a very rocky areas alot and they have proven to be a vital add on. I added some plastic from a 55 gal. drum to the leading edges on the a-arms and front plate to allow the plates to slide over the rocks easier and it works like a charm. It does take a little work to get the plastic formed just right but it is worth all the effort