I've purchased Nuespeed sport springs and plan on getting Bilsteins sport shocks with the adjustable purches in front. My question is, to even the back up with the front, would it work if I purchased some of those adjustable rear spring purches like the ones that prolly come with a KW coil over kit, thus turning the rears into a coil over set up? I think H&R has them too, but I'm not sure about for the Passat. Can these be purchased seperately? Finally, wont metal to metal contact between the rear springs and these purches make a lot of noise since theres rubber top and bottom of the springs from the factory?