Brandon - I have the Marantz 7008, and have used it to run M3's, M50's, a VP150, a VP180 and a pair of M100's.
Yes, it will be a big step forward moving to M100's and a VP180. The VP180 is an absolute beast of a center channel. It's in the same size cabinet as the M80's.
My only hesitation is this: You are going to want more subwoofage (yes, this is a word now).
The VTF-2 Mark 4 is a terrific sub, but trying to match what the 6 pack of 6.5 inch drivers will do in that 80-160 Hz range will tax your sub.
You might consider M80's, a VP180 and adding an EP800. You won't look back.
