I fucked up big with wheel selection on my '99 Mustang. It had the base GT wheel, which I later found were some of the lightest 17" wheels they ever came with and I replaced them with the OEM Bullitt wheel. As soon as I started putting them on the car I realized they were stupid heavy. Come to find out they were 17lb vs 30lb each. I swear it made a very noticeable difference in acceleration and braking, even with Cobra brakes.
TL;DR: I agree, wheel weight means alot, even on a DD. Especially on a lightweight car that is light on torque.