I've found an rb20det for under $1400-US. Only thing, it doesn't have an ECU. Where can I find one of these things? How much would I end up paying, roughly?

 

What model RB20DET is it? Is it the NICS or ECCS version?

Either way, if you don't have access to the ECU, harness or diagrams, you are better off going aftermarket.

 

I'm not sure which model it is... How can you tell the different moters apart? And what aftermarket companies would I look to for an ECU?

Here is a not so good pictures of the motor.

 

It's an ECCS version (the later variant from the R32/33 Skylines & the A32 Cefiro). The NICS version has a red rocker cover & runs dual intake runners (Nissan Induction Control System). That model was only used in the 200ZR & R31 Skyline.

Pretty much any of the aftermarket ECU manufacturers ' systems will control this engine with no hassles.

SDS, Haltech, MoTech, Autronic, Wolf, Link EMS, Microtech, the list goes on!