"That said, 300 RWHP in a Boxster in a well prepped car will give a GT3 a really hard time, one of my customers has already done that.. The key is not upsetting the car's balance." Quote Jake Raby
This is very true. Still more power can be made by adding displacement (LS1 motor) or adding a turbo, but then you have a car that is a lot more difficult to keep the shiny side up.
The car is so well balanced that too much power becomes a problem. I spent some time this weekend in a highly modified 944 Turbo S at the track. A very fast car but difficult to drive fast. The basic rule is " When the car comes on boost, make sure the steering wheel is straight... even if you are mid-corner, make sure the wheel is straight.
We turned some fast laps but it was a lot of work and we were very inconsistent. Several times I thought we were going in the weeds.
My little 2.5 Boxster is a push button sports car. Easy to drive at 10/10ths and easy to reel back in when needed. It can be driven very consistently lap after lap with no issues. By choosing more technical tracks and avoiding the super speedways the Boxster is in it's element.