Hi Chris,
Might as well put my thoughts into the mix.
I have a Naim 12s (dual/split railed) I use a Hicap then into a CB 250. Some say the 12s is one of the better pre amps Naim ever made, it certainly is better than a 32.5 by some way.
I use Linn K20 and Naim interconnects my sources are an LP12/Ittok/Karma and a Linn Majik Streamer into Shahinian Super Elfs when using the Naim system, sometimes the Linn Saras if I want the walls to shake.
I have other pre and amps, a full Linn system including Akurate 212 speakers and Linn Saras, I also have the full Quad valve Classic II with QC24 pre amp.
Each system has different things that it brings to the listening experience.
The Naim has a forward quick sound the image does not have the depth the Quads have, however on some types of music it rocks, which is why I keep it.
The complete Linn system is fast and dynamic with images you could almost touch, much faster than the Naim, the leading edges are so easy to make out, the image is a bit flat so not 3D like some systems give, but again on certain types of music it sounds amazing, I use Audioquest Mackenzie interconnects and Kimber 8TC with the Linn system.
The Quad valve set up into Shahinian Super Elf's is not that fast, it is nice and easy, quite stunning 3D image, nice on simple stuff, but it won't make Pink Floyd rock the room however on female vocals it is stunning the emotion it brings is better than the other two systems I have, I use Mogami cable for both the interconnects and speaker cable and Eichmann plugs for the interconnects and speaker cable.
I used to have Shahinian Arcs but they are on long term loan so will get another pair of Shahinian speakers again, soon I hope.
I have used the Linn Majik DSi integrated, all in one streamer, pre and amp, if I was starting new I would buy one, yes second hand, they are great, the new Linn Majik integrated I would not buy.
Basically the type of music you mostly play will make a difference to what HiFi will sound good to your ears, so if you have a system that sounds fine on most things you listen to, don't change, play more music.
The 72 has a sound that is slightly different to the other Naim pre amps, some prefer them, maybe you fall into those that do not, changing the power supply or pulling boards will not change it's basic sound signature.
The biggest change you can make to any HiFi after getting your room right is speakers, try and listen to some Shahinian, you might be very surprised.
All the best on your quest.
Cheers
John