What megasquirt?
 

I have a 1990 so obviously its a 1.6l and I bought a 1.8l with a full turbo setup a few months ago i was just wondering what mega squirt i should use i was told to use a 1.6 megasquirt a 1.6 wiring harness and just hook all that to the 1.8 and i should be fine but i just wanted to check and make sure before i buy a 900$ ecu.
Thanks

You buy the MS that corresponds to the wiring harness in your car. Since you have a 1.6 car you buy a 1.6 MS.