The Whipple is cool. The lowering is cool, if done correctly. The Wheels are an acquired taste at best. I'd have the shop check out the suspension and just how they had it lowered. Some suspension kits will put the rear shocks at such an angle that they bind during their travel and can cause the rear to bounce on rough surfaces. In the front it sounds like they used more than drop spindles. If the front springs are to short the front end will be bouncing off the bump stops, this will be easy to see if the lower control arms are hitting the bump stops. Correcting a few iteams and you have a very cool "Burban.