I have four B&W 801's, two 603's and a B&W center

The wattage you need depends on how LOUD you plan on playing them.
Normal (background) music is usually less than a watt per speaker. Loud enough to cause permanent hearing damage will need a thousand watts per speaker.
If you plan on listening at rock concert levels.. 100 watts is not enough. If you plan to listen only at moderate levels.. the 100 watts is 'adequate'... but I would go for 300 @ 8ohms per myself If I needed amps for those speakers

The N801's are very efficient. Playing very loud passages on mine I am using about 30 watts on peak passages. It is more important to have an amplifier that can handle the load they present easily.

classe and b&w are a marriage made in heaven. I'm sure there others (I have 805's and run with a pioneer elite HT receiver but can't compare to the sound I heard with the classes.