Just out of curiosity I removed shielding to see what ecu I have on my94wrx, I found a unit by Unisia Jecs Corp with Z4 printed on it. A few wires have been re soldered together but matching ends i.e green/black to green/black. Why would this be? Is this the standard ecu for the MY? what ecu upgrades are available? what are the advantages and costs? Hope you can help me?