I was basing my speeds on the vbox gps which is probably more accurate than the speedo. I have been watching a couple of videos of really fast drivers on the same track and they use 5th in a Roadsport. I don't as it feels like it's slows down and there are two extra gear changes which costs time. Obviously it's at times when I'm too busy to study the Speedo. I was on the limiter in 4th at Dony past the exhibition centre, pit straight and Craners. I know the 310 is really good but I like working the lower powered car and trying, without too much success, to keep momentum in the scary bits.