Good god, what are we talking, a couple ounces ?!?!? Hell, skip the fries at lunch !!!
As for the ackerman, zero is fine for straight line racing but the OP's application (as far as I know) and mine would be a street car and you do want some ackerman or you end up with significant scrub.
As much as I agree with the above on ackerman, defining the problem as "scrub" could be misleading, as scrub is more usually thought to be related to SAI type issues, although your point about lack of ackerman is still understood to be clearly negative.
And it doesn't take many fries to soon add up to a 1/4 pounder.
