this is Stingray0007's jealous son commenting here.. i absolutely hate the fact he's got two - even worse when they are a dream to hear and ride aside - hopefully one day i'll inherit the hp4 from an aging 53 year old man :P (being 18 sucks for just this reason - all i can do is sit on the back)
as my son said yesterday on the back, it was scarily smooth! it'll be interesting to see it fitted to the standard bikes, i reckon a few more years and it will be a standard kind of part, will take a while to pull the prices down though! what a beautiful machine it is though!