surely for the cost of a NOS kit on a focus RS, you could buy engine mods that would give you a permanent 25-50bhp power hike?

and remember NOS is useless when the bottle is cold (i.e. most of the year round) and even with bottle heaters it takes quite a while to warm them up. and i cant be arsed lugging the bottle in and out of the car to keep it warm in the house etc. so it tends to never hardly get used.