Run 50 yards as fast as you can. Then do it carrying a full 5 gallon bottle of water.
Notice a difference?
Okay, so that's a little exagerated, but you get the idea. 5 gallons of water only weighs 41 pounds. 200 pounds of anything extra will slow down your car at least 2 tenths, IMO, maybe more. The best way to find out is to pull it out the next time you go to the track.
Take care,
~Chris