Absolutely brilliant!! Most fun i've had in AC for a long time. Earlier in the day I bought the new GT3 car from RSS, and then spent the rest of the day riding a vintage sidecar on every track I was testing :-)
My only wish is that there was a way to hide the driver's helmet so I can sit further back with a triples setup, but I expect that isn't possible.
I really hope you can do more sidecar mods in the future as this works so well. How about some IOM TT style modern outfits?