My experience with the JPI 760 installation was the same as Mark's. The STC covered it. No DER required.
I would encourage you to consider using two JPI EDM-800's instead of the EDM-760 model (albeit at a significant cost increase and additional panel space). While the 760 does 90% of the job, there are a few extra probe options available for the 800 model. I think most notably the 800 has a digital RPM (which is missing from the 760).
The 800 also has MAP, Oil Pressure, % HP, IAT & CDT (the difference indicates the cooling drop across the intercooler).
Regardless of which unit you choose, I strongly recommend the optional oil temp prob. The competition from Insight is the GEM and to my knowledge it has not Oil Temp option.
Check out JPI website and see if the extra probes are of interest to you.
http://www.jpinstruments.com/main_Frame-2.html