Standalone ECU, a bit over the top for most applications. A DTA ECU is much better value for money at ?600-1150 depending on spec.

that sounds good.so there are special ecu-s for s12.where can you get them,and how reliable they are?any personal encounters with those?

No they are generic ECUs for all cars - you'd need to either modify your wiring loom or have one made to suit it and then get it mapped on a dyno.

I have a DTA S100 for another project of mine but my S12 will eventually run an S60.

http://www.dtafast.co.uk/compare_ECUs.htm