Good points. She'll be sitting about 15 feet back from the built-ins, which are about 15" deep. I would make sure that the speakers stuck out just a tiny bit in front of the ledge, and hopes she keeps them that way.
Comparing the M2 to the M3, is the M3 substantially larger than the M2? I will go and look at the specs, but that doesn't always give me a good sense of actual "size." Also, which will give her just plain a "better" sound? I don't think she's gonna listen very loud, and the parties that she has are usually tamer gatherings that don't require a large soudn system.
(To give you an idea - she's upgrading to a 34" DLP and surround soudn from a 1994 19" tube and a boombox). Anything is going to be a vast improvement.
