Here we have a performance ECU for the MGTF 135.
This will do the following to your car:
10% power gain
3-4mpg improvement
Much better throttle response
Raised rev limit (for max power/more speed through the gears)
MIL light removal and an optional exhaust crackle
Here is the link to the data for the ECU:
https://www.kmaps.co.uk/mg-tf