I can kinda help answer your question. I've never driven a base G80, and I can't comment on manual vs manual. I do, however, currently own both an M3 and a MK8 R. My M3C is a 2WD, and my R is a manual. I also wanted to have a manual (perhaps the one of the last few on offer) around to satisfy the third pedal itch. Usually, I'll switch between the two every week or so (my fun cars occupy a tandem garage bay, so it takes a bit of effort to retrieve the one in the back). Others may disagree, but I think the M3's power is much better suited for an automatic transmission. Conversely, the MK8 R's manual is what makes the experience fun and engaging for me. They are very different beasts, and I find that they complement each other well. Both will jeopardize your license if you're not careful. And I don't miss the extra 190HP when I drive the VW.
