I was lucky and got one here in the marketplace for a good deal. The cheapest place I know of is 380 (msrp) but they do free shipping. If you order from kmac directly you end up paying over 400 because the shipping is so much.

Here is the link, the picture is of the rear kit but the part number / description is for the front.
Kmac 502016J this was posted by another member some time back, I think they have promos and coupons sometimes so you may be able to save a few bucks that way as well but you would have to wait. I suggest checking MBWorld for sale section as well, I have seen them there from time to time.