K.I.T.T. is the more reliable vehicle, and in a straight-out road race he’d easily take an early lead, get a lock on the race, and be able to track Herbie with radar to make sure the bug stays behind.
However, if we’re talking a variable-route road rally, Herbie will have more opportunites to maliciously sabotage the route and and pull off a gravity-defying feat that leaves K.I.T.T. in the dust, but only if K.A.R.R. has already been treating Herbie like a shmuck.
If it’s a race on a track, even better, since you can pretty much guarantee Herbie will be leaving oil slicks just about everywhere to guaranteee a win.
Of course, Wonderbug may zoom to the rescue and fly to the finish, but only if race officials allow the dusty jalopy to the start line.
Winner gets to exchange hydraulic fluid with Your Mother (The Car)!