I don't know of anyone that has used one on a turbo buick, but I have used one of the older AEM EMS systems on a turbo mustang. The interface was great and the system worked really well. The only downside was that the unit seemed to be sensitive to "dirty" ground signals.
I would think that the AEM stuff could be easily set up to run on a LC2, however for the money I think something like the Holley HP/Dominator EFI is a better bang for the buck.