I've only just discovered this mod and all I can say is WOW!
They physics seem just right - not as 'hard' as GPL but then these cars weren't as hard to drive. It was all about precision. The cars look fantastic, with model variations to reflect the season. The immersion is fantastic with all the right tracks and trophy races alongside the main Grand Prix.
I wonder how many more copies RFactor would have sold if this mod had been available when it launched? This is GPL 2 as far as I am concerned. The only other Rfactor mod that comes close is GP1979.
I've also found quite a lot of TV coverage of this era - highlights from the Dutch GP highlight how surprisingly competitive the Honda was:
http://www.youtube.com/watch?v=itfBTH6uMDQ
Dare we hope that this might be modified for Rfactor 2?