If you go to the FPV website and look at all of the images of the cars on the salt flats, they CLEARLY have 20" rims and they're a different design to the B series rims, but yet, they kept the same rims from BF to FG. Check out these pics: Look at the profile of the tyre on the F6 here Definitely 20's Similar to the argents Maybe they made a last minute decision to save the rim upgrade to the series 2..?