Sagging in the rear. The car not me!

The other day while helping my brother pick up his new A4, the owner of the dealership and I got talking porsches and he mentioned that my car looked a little low in the rear. After checking it out on several times and parking next to other 911's to compare, I think he's right. Is this common? Is rear ride height adjustable on a 964? Anyone know the ride height spec and where to take measurements? One of his sales staff suggested lowering the front to match, but I drive it everyday and don't want it too low.

I'm a new owner and don't have manuals yet, so any advise is appreciated in advance.

Thanks!