I had so much fun with mine, I bought the two-ended Safari version, too. There's very little they need right from the box. Just a centrally located weight, and of course, truing the wheels and tires all around.
SCX made a series of narrow-track, small cars that run superbly out of the box without magnet, which is remarkable. Really nice cars if you can enjoy that kind of racing. Not exactly mainstream interest though - that appears to be more like Slot-it and NSR. SCX has folded I think?