Never take it to an auto car wash. Wash it yourself.

Be careful to not curb the nose while parking.

Install a clear bra immediately; it has saved my front end numerous times.

Lots of wax and/or sealant, especially on the front and rear. The rear gets ridiculously dirty while driving in the rain :(

Thanks everyone! :) How often do you guys wash your Z? Do you wax everytime? I feel that washing the wheels takes a lot of time...

If you want to lower your car, get the Swift springs unless you're going the coilover route.
I believe that the Swifts were designed and tested on a Nismo. Check out my photo album to see how the drop looks. There is a review thread or two here in the forum.