Jad wrote:For street driving it probably isn't worth it, a good alignment should suffice.
I have to agree with Jad on this--if you aren't going to autox the Boxster, don't worry about it. You don't even need an agressive alignment if you aren't going to drive it at 10/10ths. A street alignment would be better for tire wear anyway.
That said, I have dutifully paid the extra $275 to have all my race cars expertly corner-balanced (thanks, Steve!), as it can make a difference in the steering balance of the car when turning one way vs. the other, as Jad said. I doubt if your Boxster could be that far out of spec that you would be able to feel the difference, though. The factory does a pretty good job of it, and you would have to have a pretty gross imbalance to notice it in street driving, since you rarely approach the limits of grip in your tires (hopefully).
There can be quite a few different approaches to corner balancing anyway--I know of at least 3 different methods employed by road racers (ignoring the bizarre setups in roundy-round racing) that may result in greater variances than exist on stock cars from the factory. Some people advocate matching the diagonals (weight of RF+LR=LF+RR) while there is another camp that maintains the correct procedure is to achieve the same weight distribution ratio on each side of the vehicle (LF/LR=RF/RR). There is also a dissenting faction who contend that small steering imbalances can be tolerated and corrected by the driver, and that what is most important is maximum braking capability in a straight line, where making sure the two front corners are equal is paramount, so that one side does not lock before the other (LF=RF, and then get the diagonals as close as possible.) The differences in these three methods could easily be larger than any imbalance your car is currently suffering.
Setups are largely effected by personal preferences, tire choice, and the type of tracks that are run, but if you're not racing, why even hurt your brain over such subtleties or pay the extra $$$? Just drive it and don't worry.
TT