I always keep mine on a pcar barttery tender. Probably a pain in the *** for a daily driver, but I had dead battery issues early on, which are now resolved.

 

I recently purchased a 06 S and the first thing my wife commended on was the slow starting, not the price, or car color.
I took it into the local P car dealer and was told it needed a new wiring harness from the engine to the starter. They said there is a connection that developes a high resistance at the starter. They are replacing it Friday. I will update after the installlation.