Hi Paul,the cost oh the cost ALMOST 3000 bucks.I know i'am nuts now.But in my defence I can only offer this I wanted to do it right and then take it from there.Plus i now have a spare set of shagged cylinders awaiting re- plating and porting should i ever be able to have cash again in this life.I also have a set of older ethos pipes for the bike now.As for the B pistons yep Honda NZ tried it on me as well but my parts are now on ex-Japan order.You should dyno your bike and post it you never know someone out there might have some tips for more ponies theres a guy on the Aprilia site with a claimed 70hp on an aprilia rs 250 and he says they have no probs with the sv's he did some serious squish band work though.