Recommended crossovers for Maggie 20.1s

A number of contributors to these forums have voiced dissatisfaction with the stock Maggie crossover units. So what do you recommend as a replacement that would provide noticeable improvement? The Mye Stands have helped a lot, I could get larger amps (using Krell fpb 350 monos) but don't know a thing about crossovers.
sorry for the lack of any concrete information but I remember reading (years ago) in Stereophile or TAS that a costly crossover for the 20 (or 20.1) resulted in a minor upgrade. The concensus was that money was better spent elsewhere. I know the 3.6 and 1.6 can be easily upgraded this way but, according to this article, the 20.1 was apparently not.
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Puerto, 20's and 20.1's always sound better when biamped with an active x-over in my listening experience. I would recommend the Bryston x-over, I use it in my system, which I believe retails for around $2800.00 these days. Also take a look at my recent review of Martin Logan Depth subwoofers, used as a pair, that has brought my 20's to much higher level of performance across the board.
I had the Marchand solid state, which was just OK. I suspect the Bryston is better, and the Pass Labs is better than that if you have the $$$. I haven't hear the tube Marchand. I ended up with a 2-way custom Xover made by Tom Tutay. It wasn't cheap - but it was GREAT! Really opened up the system. Ultimately sold it all because the Maggies were too big for my room.
Thanks much to each of you that responded. I will check out the Bryston product and follow-up on the related thread on Audio Asylum.
Passlabs XVR1
I know I own one. Used with 20.1 for 5 years.
Bryston 10B is entry level and the only reason I didn't get Tom's cause it fitted without balance.
Even with the 20.1 if you upgrade the crossover, it may indeed make a big difference - not having anything to do with the crossover, but because of the implications it has on the amplifier relationship. You can go with something like Spectron Musician III for the bass amp, which is 800 watts/channel, and then go crazy with nice sweet sounding lower powered amp on top end. You get 4X the power out of an amp when using an active crossover, in part because of the lack of need to control the other sides of the audio spectrum. For less money you can go Bel Canto kilowatt amp.

Imagine an 'effective' 3200 watts on that bass panel, and whatever amp you are running being dedicated to the higher frequencies.

Definitely go XVR1 or consider DEQX if you are so inclined. That is a whole world. Not sure what level of DAC you are at - while the DAC in the DECX may not be up to 10k DAC standards, the whole package you get may have a net improvement on the system.

For the 20.1 I wouldn't go under XVR1 or DEQX, although the Bryston unit will of course also work just fine. Nothing less than that, though.
I agree that the Pass is likely great. I didn't miss a gain control on Tom's Xover at all. It just sounded great. In any case, I experimented with solid state amps on the bottom (Bel Canto Ref 1000, Parasound JC-1's, Bryston) and reasonably powered tubes on the top (VTL 450). There was a notable difference between the naturalness of the VTL's and the SS designs, and I ended up with two pairs of 450's biamped for each speaker. I also found that power seems to be more critical for the mids/highs - don't know why - but Bea at VTL reported the same finding for the Maggies (I didn't believe her at first).