One other thing to consider...
The 911 handles much better with a full tank of gas and the stock massive battery
.
I always top of the tank before HPDE. Thats an extra 300lbs in front. Leave in the tool kit, etc...
This weight really offsets the happy tail movement of the car...
The prior owner of my car added a 964 turbo appearance kit to the 930. The front bumper is HEAVY metal... I think this really helps the handling. I haven't spun the 930 yet. I have let off the gas in a turn, but it hasn't spun...
I had actually wondered, if adding 50 lbs of lead to the front bumper in many of these cars would permanently solve the issue. Thats not a lot of weight, but would give you a near 50/50 weight distribution...
There is a reason porsche put in a tractor trailer sized battery in the front of these cars...