It's not happened before. All the members of a team must run a different car. Most I've ever seen is three of a particular car out of the hundred entries, and they tend to be iconic cars like Escort Cossies.
All cars run a set build tested to give relatively equal laptimes over the course of the series. OK, so it's a bit brave to run the GMC van but it's only a bit of fun. Tuning is free. Take the mick and run an illegal build and it's a DSQ, followed by a ban if you do it again.
Seriously worth a look. I've run the last three seasons.
To be fair they tend to faff around for a while before it gets going.
Nominal start is 8pm, but they don't hit start in the qually lobby until 8:20pm in case of connection issues. Takes them a while to sort the lobbies as there's usually 60+ racers any given night. Race usually starts around 9:15pm so you'll be done around 10pm.