I know a local drag racer who replaced his stock aluminum driveshaft in his Pontiac Firebird.
It was a 6 speed with about 650 crank horse power, and an absolute HOOT to drive!
He replaced the driveshaft with a carbon fibre one ONLY for the reliability.
It did not change his ET.
With light weight wheels and tires,for example you reduce your weight, rotating weight, helping handeling, braking and acceleration.
$1000.00 would buy you light weight wheels, AND lightweight seats,
for example.