Should I consider the newer Audio Research pre & power amps, when I play records not CD's

Get an ARC pre-amp and a good SS amp (maybe the widely hailed Benchmark?).

I just bought a used ARC LS25 MkII and use it with a 20+ year old Sunfire amp on maggies.

I am just stuck on tubes. I love the warmness they offer. Yes a pain but I feel they are worth it. I love Magnepans an had a pair of the ARC Magneplanar Tympani's back in the 70 and loved them. They took up the hole room. They have come a long way over the years. 

Don’t underestimate the Classic 60. It punches way above it’s weight class. One of the reasons is that it use 4 6550 tubes per channel instead of 2. It is a magical sounding amp. It is not as detailed as later amps like the VT100. But it has a presence, a rightness that none of the VT100 models have. It is only the recent Ref series amps that really surpass the Classic and V series amps in a big way.

But because of it’s age you would need it gone through. At least the 4 large caps would need to be replaced. It is also not the easiest amp to bias. Then there is also the problem that a lot of modern cables won’t fit on the speaker strips. If you were to go that way I would strongly suggest the very late version that had balanced inputs or a V series amp. The V series is very similar to the Classic series but is balanced and came with KT90 tubes. 

I have found that over the years system synergy has a huge impact on your sound.  Make sure to take a holistic approach to your system, not just a "that's the best component". Unfortunately, only by a lot of work can you start to dial-in the synergy unless you copy completely a system that you have heard and liked.  I have had approximately 20 preamps (both tube and SS including an ARC SP-6b and an SP-10) and 30 amps (both Tube and SS including two D-115 mkii's and a VT200).  I listen to vinyl almost exclusively. I LOVE the flexibility of tube gear.  To warm, roll-in a brighter tube, to bright, get a warmer one).  Since you are focusing on vinyl, I would seriously consider the classic tube phono amps of the 80's. ARC SP-10 and SP-11 mentioned earlier as well as any CAT or Counterpoint. The phono stages were awesome and most can be had fairly inexpensively- by far the best price/performance. In my current set-up, I am taking the phono stage of a CAT out through the tape outputs to the line stage of a Doge 8.  Simply magnificent, much better than the CAT or Doge alone and better than the recent gear I have heard (although most listening sessions also introduce other variables (components) that I don't have a gauge on, so hard to make an educated assessment.  Also critically important are the tube choices for each- 60's Amperex 6922's for the phono input and 60's GE 12AT7's for the line stage.  But the bottom is, after a LOT of searching I am now happy with my system.   I have been focused on tube amplification for the last couple of decades and until recently my favorite has been my ARC D-115 with winged C power and the same 60's 6922 Amperex's. But I have now moved to a low power SET tube amp driving my M/T 8ohm loads and an ARC SS 100.2 driving the 4 ohm bass enclosure. Cost on all this was pretty reasonable (as if any of this is reasonable) of about $4k for used CAT and new Doge preamps with NOS tubes and $4k for the new SET and used SS amps.  Whatever you choose, enjoy the music.

one thing I forgot to mention regarding phono stages (and system synergy) is that almost all of the preamps I have heard require either an external or have an internal SUT to get the most out of a low output moving coil cartridge.  So, (in my biased listening preferences opinion) if you are going to get a cartridge that has an output < or = .5mv you are going to need an internal or external SUT.  The newer CAT's have them built in, not sure about the newer ARC's, but none of the 80's preamps have them.  The phono sections of all those will work, but for me they are too noisy and lack the preferred weight.  I currently use an EAR MC-4 with a Benz or accuphase LOMC (which I now prefer) or a koetsu SUT with a rosewood signature if I am listening mainly to vocals.