Not sure if this was mentioned earlier, you will absolutely need a decent amp if you go for the 80s....which will be adding to your costs.
My Denon 1804 drove the M80s equally as well as my newish 3808. I couldn't really make out any discernable differences. I would say any amp rated to drive a 6 or 4 ohm load, works just fine as long as you are not trying to turn your house into a rock concert with 100+db on the average.