Yup, referring PVInverter_F28M35x.pdf doc is enough.Also about,
[quote]What build level do I need? (M3 & C28x)[/quote]
Depends on the feature set you're including. For all digital libraries and calculations C28 is best and for Ethernet M3 is. The project folder has 2 different directories for C28 and M3; so first check them individually. Check their respective performances and try using both cores simultaneously for the best results.
So in short, combination of both would be helpful and that's exactly why you might have short listed this mcu on the control card.
Regards,
Gautam