Sorry,
You need to put your f@t ass in the car and then weigh it, don't know of any remote controlled cobra's.
Race cars will benefit with weight reduction to a point, they would be better working on the balance , tracking and braking.
Then there's the' gray matter 'behind the wheel, a good trained driver will usually go 'much' faster than your cobra on a diet.
Street cobra's won't know the difference 100 lbs either way.
Perry.
