If you disable the ABS, you'll have way too much rear brake bias. The car is actually better with ABS. You have one of the best engineered braking systems that comes on a street car. Getting rid of the ABS is like disconnecting two of the coil packs because old school M3's were only 4 cylinder. Absolutely makes no sense. There's a reason why the BMW's in Koni Challenge can outbrake any other car out there. So, keep the ABS. As for the DSC, just press the DSC button for 5 seconds and you'll be fine. That's what we do and it works like a champ.
So, fix the system, turn off the DSC when you really don't need it and enjoy a wonderful braking system.