tuning via TPS is good in race conditions where the engine runs in almost constant full throttle position and the load varies by a small amount... As far as i know this system wont work in daily driving conditions beacause the system wont work correctly with part throttle settings (at least thats what im told). In the megasquirt software there is sucha w thing as Hybrid Alpha-N wich uses TPS as the base signal but has a correction factor via the MAP sensor.