I've had Magnepans for many years..and currently own a pair of 1.6's and 1.7's. As far as bang for your buck in a quality power amp for them, I find it hard to beat what Emotiva is offering.
I use an XPA-2 with my 1.6's with excellent results...that amp is considerably less than a grand and puts out as much power as your maggies will ever need.
What type of surround/center channel speakers are you intending to use with the 1.7's?
I would probably first try the 1.7's with that Pioneer Elite receiver you already have. I read a couple reviews on it and the power amp section seems to be pretty highly thought of. It may just be all you need..depending on room, surround and center speakers, volume preferences, etc.