I'd long been wondering when Grant would get around to this one:
On the latest Mythbusters - the JATO-car "This time for sure!", which deviates ever further from the original yarn, while retaining the Impala - he's finally hooked up a computer-game steering wheel and pedals to the RC box, to allow driving the 1:1-scale RC car like a car.
There's still the matter of having a totally separate radio-command system for firing the rockets, but I'm guessing that's a COTS secure system made for HPR or possibly blasting.
Oh, and on the Science! front? They keep bandying about a conversion factor for thrust to horsepower. There's no such thing. The units are non-equivalent. Thrust is force (pounds, Newtons, dynes: mass times acceleration, e.g., kg*m/s^2); power is force times distance per unit time (horsepower, Watts, BTU/hour, e.g.: kg*m^2/s^3). Yeah, you could assign a rocket a horsepower rating based on fuel consumption or (almost equivalently) heat output, but that ain't how horsepower ratings work (though if you used BTU/hour instead, it would make sense: treat the rocket as a heater).
And in the department of I could'a told you that: if you're going for maximum range with your rocket car, and you're not giving it fins like a Cadillac (nor RCS, nor engine gimballing, nor active aerodynamic control surfaces, nor any other way of keeping it pointed straight), best results will be obtained by timing Brennschluß for just before the car leaves the ramp. Not a couple of seconds later. If memory serves, they'd already seen the nose-comes-down-leaving-the-ramp effect (because Gravity, duh) in at least one earlier episode (possibly involving an old TV show about hazardous ducks or something), so it should be no surprise that the thrust vector, immediately post-ramp, would be Highly Suboptimal.