Thanks babybolt. Did not know of the rake angle. With a spirit level in the door sill, the car sits dead level, maybe 1/2 of one degree down. And yes, the OEM plastic spoiler.
But, my question still remains. It looks like bolting on taller rear spring shackles to raise the rear maybe 1" or so looks to have them hit the rear lower valance. Have you done so w/o interference?