Yep, just had my RB26 mapped with AEM EMS. Works really well if you ditch the CAS and run Crank/cam sensor. Makes about 520 bhp on stock engine, HKS cams, large injectors, steel standard R34 turbos. You need to find a tuner who is experienced with AEM. However, if you can map ecu's, I should think the AEM software will be easy for you to use though.
No am in Denmark. The guy who did it for me pretty much only works on AEM so I expect it was ok to install (we rewired the whole car which tool most of the time I think). He had issues with the CAS unit, but it may have been due to the sensor I had which may have been bad (although I got it from a tuner in the UK). We just decided to ditch the CAS to have more control and to avoid wasting time troubleshooting. I know theres a CAS fix from AEM.