I remember the 'ding dong' RX7's......it was more of a warning to say that the rotor seals were about to exit the engine than gear change advice though!.
Well whatever it was there for, that's how he used it
Funny you should say that though, cause that's exactly what happened
He then grafted in a 3.9 V8 from a Range Rover. Spoilt the car a bit, but it sounded great