While trying to learn how this stuff works in theory I found bc127 wich in my eyes looks like a good (better?) alternative to rn52.
It supports BT4.0 and what I could find it's much better documented and have more frequent firmware updates.
And the commands makes more sense to me than those used in rn52.
Saab 9-5 Aero MY01 AS3 - 270hp/240hp Biopower
Saab 9-5 SE MY00 AS1 - 210hp+