Bigo, the answer depends on your speakers...
If you need the power, your should move up to the 120s. Otherwise, the improved sonics of the Magnum Series is the way to go.
As an example, in speaking to Mark O'Brien about my Coincidents, he told me also has a pair from of Coincidents(different model). He told me the speakers are efficient to the point of the 88 being overkill. The man actually pleaded with me not to waste my money on the monoblocks. That's another reason I root so hard for Rogue.
In this type of situation, opt for the Magnum, and spend some time speaking with him. He would probably work with you to increase performance even to a greater degree.
However, if your speakers need more power, go for the 120 monos, and upgrade later if they aren't Magnums.