I just got a 2004 and had a few questions.

Any tips on keeping/caring/maintaining the car? Any issues I should be aware of?

Also, do SL55/65's use different sway bars? Can they be retrofitted?

Don't bring food into the car.
Let Renee drive every now and then.
You'll be set

Lets see how it looks?

Congrats on the car! As I said on Fchat, good choice in car especially if you want a bit more power. Renntech has some nice options for the 600. As far as caring issues, nothing different than any other cars. You should have a while left on your warranty so all should be good. Lets see some pics!