I don't think they are that much actually. I recall Sean saying his mountune one was just over a tonne. Marco might be best person to ask on a price for modding your own one. As regards need, I suppose you never know when it might see a track for some action, but in reality I've done a couple of days with my standard one with no obvious problems. Maybe with slicks it would be worse. I think its just an extra safety measure that in my circumstances I would use.
