I know this is a relatively stupid question, but I was just curious as to how fast a car (the Rx8) and go in the reverse gear? (Not intending on trying this anytime soon)

I think I got it to 20 before in reverse. There was a traffic jam on the highway right after the rmp I was going to come in from and no one was behind me so I had to quicklyget out of there before I was blocked. Toobad the other route I took instead was also badly congested.