Something else is burning up your starters or you should try OEM. It's not the motor
The 1.4kW starter is also found on KIA motors, possibly from the model with the FE3 engine in it. I can't quite remember how I worked out the right one but look carefully at the number of teeth and mounting bolt pattern.
IIRC you are using a Microtech. I've found that with the MT, it's good to have the larger starter as it got the starting revs up a bit higher, which made tuning a bit easier.
Give it a try and see if it works.