I bought my a4 tdi last June and after 3 days of owning it I got her remapped through pd tuning in boldon, I was told that it would improve my mpg, bhp and torque. The torque did improve and the car did feel quicker, however recently my car had to have a new gearbox fitted due to it becoming very noisy, so I got the map removed before it went into audi to have the gearbox replaced (under warranty thank god £3,000), since I've had the map removed I am getting an extra 50+ miles per tank and I've not changed my driving style, I wont be getting it remapped again.