20MPG when pushing? 9-10 on the track here, and a simple cool down lap is all that is needed.. you don't have to leave it running.

 

The majority of people in Japan these days who street race, track race or tune their cars in anyway either has an additional turbo timer installed or something like an innovative alarm - The Boomerang 2000 which has turbo timing plus remote start features as well.

It is definitely good to leave your car to cool down after driving it hard whether it's NA or TA. How much petrol do you waste anyway? Don't even count, everytime when you blast VTEC you forget all about saving fuel so why start now? It's just basic engine care and maintenance, doing little things add up.

I have a Boomerang 2000 myself and I'm sticking by the "Cooling Effect" period. It's really all up to you, nothing more than that.