First--I would have a thorough audition and listen for any "buzzes" or "rattles", and to make sure the highs are there. Maggies of that age (no matter how well taken care of) are susceptible to delamination or corrosion of the wires (especially tweeters), just due to age. You can also run your fingers over the upper and lower areas of the socks to feel for the "banana peel" lifting of the wires from the mylar diaphragm. Often, a strong flashlight can help you see through the socks.
As for power requirements--pretty much all Maggies are a rather static 4 ohm load--no dips or spikes, a relatively flat impedance curve, so your amp must be comfortable driving a 4 ohm load--amps don't "produce" ohms--ohms are a measure of resistance/impedance presented to the amplifier by whatever load it is connected to.
75 wpc will drive a pair of Maggies, but IMO, not really effectively--but this all depends upon your listening habits. Maggies are not very "efficient", so it takes quite a bit of power to make them "sing". Also, Maggies can and will produce high levels of room-filling sound, but will not give you that "hit in the chest" or "in your face" effect of a conventional speaker--so if you want to "rock out"--Maggies are not for you--go hunt for a pair of JBLs for that.
In addition, they are very placement dependent--they need to be at least 3-4' away from the backing wall to let them "breathe"--they are a true dipole, not a "box".that can be placed directly against the wall, so in a smaller room, they can look like "room dividers" when properly placed.
Not to be discouraging, but they are not a "typical" speaker, and not for everyone. I own two pair of Maggies and love them, but they are what they are.
