[thstone]

Remember that the stock tire widths are 205 front and 255 in the rear. This setup gives the Boxster a good amount of understeer.

By going 245 "square" (same size tires in front and rear), the car will lose most of the inherent understeer and might possibly tend to oversteer. This type of handling can be challenging for some drivers (which is why Porsche built in understeer).

When running a square tire setup in Boxster racing, we have adjustable sway bars and use sway bar adjustments to keep the car balanced (not tending to understeer or oversteer). In your case, a stock Boxster does not have adjustable sway bars so if the car is tail happy, you're just going to have to be fast to catch it.

I'm not saying that the car will become unmanageable; in everyday regular driving you'll probably never notice it.

But... my guess is that you will figure out pretty quickly that the front end has a LOT more grip and if you start exploring just how far that grip goes then you may find the point where the rear loses grip before the front (oversteer). Or even if you're not the type to test out the limits of the front end grip, the same could apply in a situation where you have to make an emergency maneuver.

This may not be an issue but I wanted to let you know what to expect.