[LastHobbyPromise]

Hello Last,
Most people slot-car start drag-racing simply by having the power switched off and holding the throttles fully on then switching the power on. First car across the finish line wins.
Probably best if you try that a few times before spending any $$$.
The full experience of staging, start Tree Lights, reaction time, elapsed time, terminal speed and such should be your ultimate goal - its not a simple sport.

Leo

 That first part is not racing.
 I actually ran my 71 Kawasaki 500 at Irwindale drag strip in So. Cal. in the 70's, so the second half of your post appeals to me. :)