Speaking as a past Magnepan owner, what I'm hearing is that you own a Ferrari and you want to put a diesel engine in it, or is it vice versa? Had the 3.5r's that were some of the most exact sounding speakers I have ever had. I played with a ATI 1002 and a Audio Research VS55 and they didn't want to sing at all. With a McIntosh MC-7270 or a Rotel 2-channel biggest they ever made (don't remember the model number), they were beautiful. Maggies are slightly more efficient than a slab of marble.
Electrostatics and tubes
I am looking to get some new to me speakers, I've been looking at options and would really like to try a set of planars "electrostatics". I have read or heard somewhere that as far as speakers go they tend to be inefficient (85 to 89) vs.90+(db) on the Klipsch or Dali's I've been tossing around as a standard speaker option. I guess my question is would I need to worry about any over heating issues. I plan on using plenty of power with a set of VTA, M-125's to power them. I am looking at a lower budget set maybe Martin Logan ESL 9's or Magnepan 2.7i . Just wondering I would hate to over heat a few hundred dollars worth of tubes if I don't need to. ¯\_(ツ)_/¯ don't roast me to bad I cry easy 
thanks.