I don't know too much about them, except they have the 2.2 H series out of the ATR (may be slightly different) and have an LSD.Fanks. I've not had any experience of those. They were 5th gen only weren't they? I do quite like those if done nicely. TBH I have no idea what kind of speeds this thing does but it's certainly good fun and makes a satisfying noise. I think the fact it's old and low and noisy makes it feel 100% faster than it actually is.