Magnapan 35r and Hegel C55 Amp

I would think the 300 into 4 ohms would be fine unless you’re a volume freak.

Hard to imagine that wouldn’t be fine, but you’d be better off posting this in the “Speaker” forum as you’ll get more thoughts from Maggie owners. 

At 86 dB sensitivity and 4 ohms 300W should provide dynamic peaks to 110 dB - sounds pretty adequate. And FWIW I believe the mfg specs power to 250W.

No need to bi amp

Bi-amping is a waste of money.

Why is this in the 'Music' thread instead of the 'Amps/Preamps' or 'Speakers' thread? You're likely to get a lot more responses.  

As long as ur amp supplies plenty of current, that’s the key for Maggie’s. Not watts. I’m sure your Hegel is fine. 

Good advice here OP 

I have the Maggie 3.7's and use the Hegel H360 integrated.  420w @4 ohms.  I can tell you that you will max out the speakers before maxing out the amp.  Most Maggie owners will get what they want out of them at medium SPL's, so you've nothing to worry about.