my daily comute to work included 20miles of motorway, and 5miles of heavy traffic...and with 380bhp, i would average at 30mpg during the week....on a steady run i did see 38mpg on a few ocasions....but to acheive this i had to drive really steady, and poodle about

closed loop iis very effective imo....and its not expensive at all if you already have L8....just a sensor, and msd chip....mine paid for itself in a month