so, found some new motorcraft dg-515 coils on e-bay for just under $40 bucks a pop-free shipping. is this a good deal? could these be new, old stock? under the impression that dg-529 were the newer/newest style. kinda thinkin' 'bout pullin' the trigger on 8 of 'em; 90k on a 2000 ls8, and vcg...