a pre-amp around $4000 for my system

Without knowing what you're looking for in a preamp, all I can say is that I am very happy with my McIntosh C220, a tube/SS hybrid full-function preamp. List is ~$4K, used usually under $3K. I did replace the stock tubes with Mullard 12AX7 reissues, for about $80. Smooth, detailed, free of listening fatigue and wonderful soundstage width and hieght. I am thinking the system you listed might benefit from having some glass somewhere in the system, and the preamp is a great place to add it.

Get a TRL Dude and know you won't find a better sounding preamp for up to $20,000. This is a simply fantastic sounding gem that can bring sweet music like you have never heard in a component. Ya, I am a huge fan and owner.

Grannyring's right, there's a TRL for sale $3500.00 you won't regret it.

With "very" ss Bryston power amplifier, IMO, the best match would be lush Joule-Electra LA-150 Mk2 or "SE". You can call them direct to ask if they have demo or slightly used unit for your price point. You will be able to see what your Maggies are capable of !!!!!!!!!!

Audio Research is recommended for magneplanars.