Well this morning I brought the Z in to have the headlights checked. I have a good rapport with the dealer/service and was allowed in the back when the car was up on the lift. The tech could not believe it, but the rear sensor arm was installed at the factory in such a manner (upside down--I believe), which prevented it from moving fully. The tech actually put an 35is up on the lift next to mine to compare and sure enough mine was installed incorrectly. They have to order the part. We were joking that my car's headlights might have been assembled right after the 2-beer break at the factory. Joking aside, makes me wonder what else might be installed hastely. I still get that "thunk" from the suspension which ironically is located near this headlight sensor