hi i have a bog standard st 170 i want to do a few subtle things to it like k&n panal filter maybe decat but i dont no yet i was thinking about getting a bluefin for it but just wondered if its worth it is it noticeable will it be better on mpg allso will it remove the torque limiter in first gear that i hear the 170 has built in to ecu any info would be appreciated gd or bad ?? thanks