I'm kinda new to the plannar/magnepan world, but I am really interested in trying out a pair after all the reviews I've been reading. From what I understand these speakers are quite power hungry. What is the minimum I need to properly drive these? 
I currently have a VAC Avatar integrated tube amp. These are the stats:
Type: Integrated vacuum tube amplifier with MM phono stage and home theater (direct power amplifier) mode.
Tube Complement: two 12AX7 low noise (phono), two 12AX7 (line stage), three 12AU7/6189A (power amplifier), and four EL34 (power amplifier)
Options: Remote control for volume (motorized direct control) & mute
Power amplifier ("Home Theater" direct mode):
Output matching: 4 or 8 ohms nominal
Power output: 60 watts/channel ultra-linear; 27 watts/channel triode
Frequency response: 9 Hz - 35 kHz +0 / -0.5 dB, 3 Hz - 71 kHz +0 / -3.0 dB
Power bandwidth: 11 Hz - 63 kHz + 0 / -3.0 db ref. 50 watts
Gain: 25 dB ultra-linear; 23 dB triode
Residual noise: 1.5 mv at 8 ohm output
Channel separation: -72 dB @ 1 kHz; -60 dB @ 10 kHz
Line stage preamplifier:
Gain: 24 dB
Maximum input signal: Infinite (attenuation precedes line stage)
Noise contribution: Approx. 0.1 mv at power amplifier output 
THD contribution: Approx. 0.04% 
Tape output: Unity gain from selector, non-inverting 
Phono stage preamplifier: 
Gain: 37 dB (measured at tape output)
MC phono stage in place of the MM optional 
Residual noise: 3 mv at output (S/N ratio approx. 69 dB) 
Overload: 117 mv @ 1 kHz = 8 volts RMS output, 460 mv @ 10 kHz 
Frequency response: RIAA +/- 0.25 dB 
Notes: Does not invert absolute phase. 

Anyone know if these will do or if I'll have to upgrade? Love the tube sound . . . will I need to go solid state for Maggies? Thanks for putting up with the noobie question :) 
ok, I use a Sunfire Cinema Grand amp to drive my 1.5QRs...

The $$ allocation should likely be better speakers, then better amp.  The 3.7's are acoustically smaller than the 1.7's so why not consider those? (That is fresh and straight from the horse's mouth - may even be on their web site).

I'd love to have Bryston's too but they are not cheap - maybe the Canad. dollar will fall to 1% of where it is now...

A Maggie dealer near me is using a Rogue for drive but it is still $4k.  I'd say go for the 3.7s first and may do the same myself.
Nature boy, go read Harry Pearson's review of the 3.7's in Harry's Workshop, absolute sound and jonathan valins follow up's a good explanation of why the .7 variants are such a huge upgrade over past Maggie iterations......quasi ribbons have a LOT to do with it, the .7i's are yet another step beyond......I think you would see a night and day difference, and with amps, probably not.......
1.7 is also > 2.5r or only the 1.7i that you mentioned? 

you're saying the 3.7 is better than the 1.7 or vise versa? 
Nature boy,

The 2.5r is a very old speaker.....the 1.7 would be quite a bit better, and the I a little better than that......of course the 3.7 or 3.7i would be an even more substantial bump in's really a function of room size, the 3.7 is just a larger speaker than a 1.7......

The thing that struck me instantly on the Brystons was low level is miles better than the Pass X350 I had.....beyond that, they're both musical, but I'd give the edge to Bryston......with other speakers it could be a different matter, but on the 3.7s, I far prefer the Brystons.  I will say that I feel the 28s are not marginally better in terms of musicality versus the 7s.  If I was doing it again, I would probably stick with the 7s....

stewart, did you find the X350.5´s bass boomy and ill defined compared to the 7B SST´s? Do you mean the difference between the 7´s and 28´s is only marginal?