hey mate, you will have to make sure from ford about warranty, but im pretty sure when you lower your car you void anything to do with driveline that is effected buy lowering it, if your worried about it its probly not worth doing... there are cheaper ways of lowering than mine as I went nolathene bushes, coilovers up front, with camber kit,reset leaves, bilstein struts rear..but you could just change your springs front and get lowering blocks rear witch would only be a couple of hundred... your best off having a chat with your suspension joint if your goin ahead with it... as for the ride its great no bottoming out and no scrubbing, though I only have stock exhaust and stock wheels.... for now.... hope this helps any ....