No, off the shelf ECUs will work. But because it is a mechanical fuel injection system on these cars, most of the applicable off the shelf ECUs are designed to copy an old two spring distributor system, so you'd lose a lot of the ignition map. Also, for any off the shelf ECU you'd have to hack into the wiring harness, because the OEM units use a proprietary 11-pin connector which is unavailable anywhere. I had to pay about $5000 to get a custom run of them made. A lot of people don't want to hack into their car because it lowers the value. There are definitely people who have hacked these cars with standard ECUs though, even going full electronic MPI fuel injection with things like MegaSquirt.