what amps/subwoofers are you using for Magnepan LRS?

When attempting Vandersteen subwoofers Make sure your choice of an integrated has a Preamp out and a Main in for use of a High Pass filter or just use separate Preamp and power amp. In order to achieve this bi-amping resulting in an even better Transition for LRS,.7 and other speakers. One of the main advantages when hooking subs up at speaker level instead of line-level tube preamps are not driving into a less desirable low input impedance. The use of a high pass filter as in Vandersteen Sub 3 and prior model 2WQs use, in particular, allows the main speaker's modulation distortion to be lowered, heavy lifting of your main amplifier relieved dramatically Improving Clarity and transparency of the whole system.
The sub-three features 11 analog EQ pots clean up the in-room bass response and done without any DPS processor, The same analog system is also used in the more expensive Vandersteen Quatros, Five series, and Sevens and has now trickled down.
best JohnnyR
Vandersteen Dealer

Assuming most panel speakers thrive on current Coda Amplifiers might be a sensibly priced locally produced and serviced candidate.

Multiple smaller sealed subwoofers Crawl Tested locations dramatically reduced my rooms modes. 
If the goal with your subwoofers is to match your main speakers or any future speakers sonic presentation through the crossover region you'll need to find processing that includes auto/manual parametric frequency, slope, Q, and gain.
Adjusting variable phase and a hard crossover frequency forces you to reduce the subs gain just to get a small sense of integration matching.
If satisfied you'll save money and have no idea what your missing.   

When I had Maggie 3.5Rs I tried several class D, but that was when class D wasn’t what it is today. I would have loved to hear the 3.5Rs with my recently purchased Ric Schultz EVS1200, which is based on the newest IcePower 600w modules. Betting you would love it too.

A real bargain at ~ $2400 with money back guarantee. How can you lose?

I set up a pair of LRS on stands I build for the speaker. I spent over 2 hours fine tuning the speakers. The owner had all PS Audio Stellar components. The Stellar Gain Cell seemed a good match for the dual mono Stellar amplifiers. The Mono Block Stellars provide 700 watts be each unit. The sound of the LRS with the Stellar was musical, transparent and non-fatiguing. After fine tuning the speakers on the new stands the image focus and hall ambiance abilities of the amplifiers became more apparent. On good recordings the soundstage width expended well past the outside of the LRS. PS makes a less expensive stereo version that will probably drive the LRS effectively. The PS might be worth checking out for those in search of alternate electronics.

OP
I have been happly running a ML Dynamo sub with my LRS for months, I truly forget it's there. Talk about painless seamless integration.
Amplification is bigger dough though, using an Ayre EX 8.

The ML should be perfect for you IMHO.

I’m in the market for an integrated amp in the $2k-3k range, and a couple of weeks ago I spent an hour auditioning the Rega Elex-R and the bel canto C5i, each playing on the Maggie LRS without a sub. That they were playing on LRS was purely a coincidence, but it’s relevant to your question so here you go.

Of the two, I preferred the Rega. The bel canto probably had a bit more clarity and perhaps imaged a little bit better, maybe a little more revealing and maybe even a bigger soundstage, but I thought the Rega was more full-bodied, had more layers to the sound, had definitely better bass, and just had more of an analog sound that I preferred.  I just connected with the music better through the Rega I guess. I was listening to Buddy Guy (blues), and the Rega dug deeper and sounded grittier, which is what that style of music calls for to my ears anyway. The room was a small listening room and listening to CD (Rega CD player), not sure about cables.

I’m not sure if it was the Rega’s class AB versus the bel canto’s class D that gave it the fuller-bodied gritty presentation that I preferred, or something else.

I'm just ordered a martin logan 800x which is small, sealed, cheap, and has speaker level connections, can also be run down or front firing and I think as room correction also
I'd like to find a matching amp that I can get for well under hegel money

First system with the LRS was a Conrad Johnson PV10B with Muse 150 monoblocks.  The bass was lacking, I added two REL T5i and was satisfied.  Easy to blend in spite of all the nonsense about how "hard it is" to do that.  Placed the subs directly behind along a side wall with the speakers about 3 ft off the wall and toed in with tweets outside.
Second system with Bryston BP20 and MPS-1 and 4BSST.  No subs used.  Placement in a big room used an alcove to create two corners.  Bass satisfying enough.  OK it's not 100% integration with the subs but close enough.  Use your room if you can. 

Bottom line just buy Bryston IMHO although the tube preamp was sweet with them.

no, but great article
another winning combo referenced with the schitt monos

Just ran across this earlier...

https://positive-feedback.com/reviews/hardware-reviews/magnepan-magneplanar-lrs/

Maybe that article prompted your question. If so, apologies.