For road racing - as was stated, you must disable the ABS.
For HPDE and autocross - I'd ask you back "How good are you on the brakes??"
If you are not so good with the threshold braking, then keep the ABS. It'll save you from burning through tires when you do get on the brakes hard enough to lock 'em.
If you're good about not making tires square, then disable/remove it. You can lose some weight with the pump setup if you rework the hard lines, and you can remove the ABS computer too. It gets rid of one other item that can break on you.
joe