Replacing The Factory Jumpers On Magnepans - Does It Improve The Sound?

Probably not....

You're much better off putting those $ toward a pair of Mye Stands.

I had owned Magnepan 3.6 for eight years, this Spring I traded them in on a pair of Magnepan 20.7s.I used silver plated wire for the bybass instead of the OEM steel U devices for the midrange, and on the 3.6 the choke tweak on the tweeters.                                                  .For my 20.7s I am using a Duelund 0.75ohm resistor on the midrange. And a handmade choke (31 turns around a thin wood dowel for the tweeters.Finding out if the better jumpers can be heard depends on your system, and your ears.  I would NOT HESITATE to suggest trying the supplied resistor, and if the warming up in the sound intrigues you, then try some Mundorf 10 watt, (they cost like $1.80 each) and get some 0.5 0.75. 1.0 and 1.5 and try those out. They DO sound better than the stock ones. And if you are made of money, go for Duelund at $55 a pop. they are high end fer' sure.

I'm quite happy with the sound of the Maggies and don't find them bright, so I'm good with not using resistors.  I'd like to squeeze every bit of sound they're capable of reproducing, though.  That's why I'd like opinions of anyone who has upgrade the jumpers. 

   

You can try solid copper available at hardware stores or a piece of speaker cable and see what you think. To be honest I didn't notice a difference but like Elizabeth pointed out resistors will give you different sound.

To learn how to use your speaker with utmost excellence read my review of the .7 at Dagogo.com. 

'Bright' sound has little to do with playing around with the midrange resistors. What they do is alter the tonal balance .. The higher the resistance (from 0.3 ohms up to say 2.0 ohms.. the warmer and fuller the sound. Just sayin'. worth playing around with. Sadly the OEM resistor supplied is a complete piece of junk, and just sounds bad.

I totally agree that the Mye stands offer a lot of improvement to a pair of Maggies regardless of the model. While you are waiting for delivery because they are always back ordered with probably at least a six week wait you can experment with what is below:
Elizabeth makes several good suggestions.
If you have not done so read this short Audiogon Forum: https://forum.audiogon.com/discussions/verastarr-magnepan-upgrade

There is a lot of discussion on this subject on the Planar Speaker Asylum Forum and MUG (Magnepan Owners Group).

Great!  Thanks