hell mate
i ran my stage 3 saph cossie everyday as a daily driver to work - only work abotu 4 miles away - silly really but it was ok, it did drink petrol a bit, but on long rungs and on short trips where i was moving all the time i was returning 25-33mpg!!! thats without Closed loop! - i did look into that, but i didnt get chance to get it as the car got nicked after i owned it 7 months!
BASTARDS!!!
i did spend a few quid on it, i had the head rebuilt and did a fair amount of maintenance on it but then im a mechanic so that didnt really matter - still cost jsut short of £1200 for a head rebuild with me doing the labour!!