Cartridge Advice Please

@dhite71 , None of the above. What you want is a My Sonic Lab cartridge, whichever one fits your budget. They all have similar motors and they all are low impedance higher output MC cartridges around 0.56 mv is typical. They are beautifully constructed and will mate perfectly with your arm. The better Ortofons are very low output. The Koetsus are low output and too stiff for your arm. You would have to add a lot of mass. The Lyra cartridges would work fine but as a AR person my suspicion would be that you would prefer the MSLs. 

I prize my system’s imaging. Vinyl: it cannot do it’s best unless the cartridge gives both WIDE channel separation, and TIGHT center channel balance.

Tight center balance is not just for ’centered singer’, but it improves the location of any off-center instrument as well. Most ’Stereo’ is Phantom, and the tighter the signal, the better curtain of presentation.

Next: an advanced stylus. Surprisingly, many name brand/popular cartridges come with Elliptical stylus. Not for me, and you will find the cartridges with both wide and tight are advanced stylus, better contact with the grooves.

Cantilever: stiffer is better, increase stiffness, easier to break it. I won’t go stiffer than Boron.

If you would like to hear what's on your LP'S, then go for any medium to high end EMT carts. 

I really like the Benz Wood SM for the money. Going up the Benz line, however, can be tricky. When they swap over to ruby plates (Ruby, Gullwing, LPS), the electrical characteristic changes a lot (much high coil impedance for each output level). I’m a SUT guy so I don’t really dig the ruby LPS (doesn’t match well to SUT)...or maybe it’s also that I just prefer the warm, lush, robust "color" of the wood bodied iron-cross models. Your Ref 2SE is about ideal for the ruby models (I had a Ref 3SE), but as you noticed, noise will creep in as you go below 0.4mV. So you could try the high output ruby or LPS, but they’re carrying an AWFUL lot of coil at that point. As for the higher Benz iron-cross models - I find Zebrawood L and Ebony L to be a bit more refined than Wood SM, but perhaps not significantly so. I think you’d be looking for a bigger change than that.

I think Koetsu is a good choice if you have arm to support it. I’m not sure about the Rega arm - haven’t tried that combo. On paper, it’s too light. But on a good arm match, the Koetsus have even more of that warmth, body, and vivid midrange which I like the Benz Wood for. With more refinement to boot. The potential downside is Koetsu’s treble is more relaxed then Benz, so if the rest of your system is dark that may be too much. Koetsu’s output ratings are good, so the 0.4mV model won’t give you trouble like the SS did. Even the 0.3mV Koetsu models (Platinum magnets) have enough output to work very well with ARC Ref.

Don’t do an Ortofon, you will miss the sweetness in midrange Benz and Koestu give you (based on A90 and Windfeld Ti). The Wood SM is already better than Cadenza Bronze so you’d have to look above that, which is where they get sterile in the midrange (for me). I haven’t tried Lyra, but they have a rep of being on the brighter side.

It might be a "none of the above" scenario, as @mijostyn suggested. I've heard only good things about the MSL cartridges, so far. 

@mulveling , I would not say on the brighter side. I would say on the leaner side. It is hard to believe anyone would not like MSL cartridges. They are so easy to get along with with their higher output and great tracking ability. They are a warmer sound than the Lyras but the differences are really quite minor.