O3-911turbo brings up a very good point. Make sure your springs are specific to your cab. I know from experience on the 996 cab that the H&R springs have a tendency to sag in the rear due to the extra weight.

 

Decided to go with coilovers instead so if anyone wants my set PM me, they're still at UPS so I haven't even touched them. Dan if you can help me just return them without a restocking fee i'd really appreciate it, thanks.