What a better pre-amp Arc Ls-27 or Ref-3

Before I try to answer the questions above, I would like to say how much I enjoyed my time with both units.
If you require big bass slam, the LS27 or REF3 may not be what your looking for. That being said, I don't recall feeling I was missing anything in the lower frequencies and the REF3 certainly had good bass extension, just not big bass. The 3 had a bit better resolution, detail and neutrality. The 27 had more of the old school Audio Research warmth and what some refer to as tube magic.
Trying to compare the REF3 with the Ayre KX-R would be difficult. The KX-R is nearly impossible to place, like one component has been casted out from the chain, it's beguiling presents emulates being moved from row 20 to row 7.

The Ref3 is very up-datable. I have a customer who may be bringing one in for update.

Gary (Hifigeek), please explain how the Ref 3 can be updated?? Is the update ARC approved? I ask because a friend who bought my Ref 3 might be interested. Thanks.

Bifwynne. Please have your friend email me for details. 8o)

I have a rare REF3 LE that i had it through Steve Huntley when purchased new. The power supply was beefed up with another bank of premium caps (BG's) mounted on an acrylic board. Somewhat similar to what ARC is offering now with their SE upgrades. All resistors in the signal path have been replaced with Caddock's and some Vishay's and other mods i forget about. The only thing i do not have are the teflon coupling caps ARC is now installing with their SE upgrades. Those are proprietary so i would have to go with premium Vcaps.
If only money was no object!!!
I had him do similar mods for my REF2 Phono, DAC7, CL120's, but again, minus the teflon caps.
A sonic marvel.
I'm sure that HifiGeek can do as good a mod job as GNSC whether approved by ARC or not who cares! Personally, I didn't.
Steve has ceased modding ARC products a few months ago.
A shame. RIP GNSC.