I have a 2003 BoxsterS and I've replaced the battery a number of times. I've heard that the battery in this model is undersized and needs a largerr one. Is this true and should I get a larger battery?

 

I don't know if the battery is known to be undersized, but I do know that just putting a higher rated battery on a car doesn't make any difference in the long run. That's unless you uprate the chargeing system of the car...i.e. the alternator at the same time.