Should I buy it with 120,000 miles and a 5 speed? Where is a good place to get the ecu repaired. The car is a decent price. Thanks for all the info. What other things should I look for?

What makes you think the ecu has had it? How is the car running? Colts have a reputation for running a long time with little to no real maintenance issues or costs and are usually a pretty good buy. :)

ecu failure is extraordinarily common on all mitsus from about 89 to 93, due to leaking capacitors on the circuit board. its very common, and usually repairable by several different companies from anywhere between 200-400 bucks.