Not accounting for inflation (maybe even with inflation), I'm pretty sure that the Audi was not only the biggest single prize on daytime Price, but the biggest non-cash prize in all of daytime television's history.*
IIRC, wasn't it also the first perfect show in a few years?
*When Gene Snook pulled off the snake-eyes win on High Rollers, Trebek mentioned that someone won a Rolls-Royce on the original series.