I don't know of anyone using a "Porsche" CIS system in their cars. Does not mean nobody is, but if anyone does have one installed they don't seem to brag about it or list it as any kind of improvement. The Porsche versions are no different then the VW ones really, maybe the position of some things to fit in their cars but better or improved, nah. I have a list somewhere of all the Bosch CIS fuel distributor (4 cyl) flow rates and except for three or four they are all about the same. The three or four different ones were much lower. But if you really want or must know if the parts came from a Porsche, check the part numbers. As for any information, any book for fixing/tuning Bosch CIS systems will be fine.