With electronics it seems to pay best if you start the upgrades upstream and work your way downstream to the amp and speakers.
No matter how good your amps and speakers are, they can't recover information lost by the front end. So you get that right first- and that has this way of really making up for a lot of flaws further downstream!
I would not limit myself to ARC phono sections either. If I had to choose only between the ARC or CJ preamp, I'd go with the CJ, but no-one is holding a gun to my head and I'm of the opinion that I don't have to be limited like that.
Now the thing is, if the arm and cartridge aren't up to snuff, the electronics won't do you a lot of good. I would therefore be considering upgrading the arm and cartridge first- but you do have to deal with the issue of how much output the cartridge has and how this might affect the preamp issue. FWIW, I've found that the ability of the arm to track the cartridge properly, combined with the ability of the arm to allow for absolutely correct setup of the cartridge, will trump the actual choice of cartridge almost every time.
To put that another way, you don't have to spend a lot on the cartridge if your arm has its ducks in a row. I know this will be met with some scorn, but I'm not kidding here. I run a Triplanar, which is one of the most adjustable arms made; one day I found that my cartridge had inexplicably lost a channel, so it went back to get fixed/replaced. In the meantime I was needing my fix of tunes and the only cartridge I had laying around was a $35.00 cartridge new in the box. I figured, 'why not', set it up with the same care I would a $8000.00 cartridge and see what happens. Well it tracked perfectly with no hint of stress on real torture tracks, but sounded a little up front (well, more than just a little...). But then I realized that it was a moving magnet and loading is a big deal with them, much more so than moving coils, so I experimented with loading and the up front quality went away: the cartridge was smooth, fast, detailed, extended- in fact the only real difference I could hear is that it obviously had more output so the noise floor was lower.
So you might take this into account with your update scenario.
No matter how good your amps and speakers are, they can't recover information lost by the front end. So you get that right first- and that has this way of really making up for a lot of flaws further downstream!
I would not limit myself to ARC phono sections either. If I had to choose only between the ARC or CJ preamp, I'd go with the CJ, but no-one is holding a gun to my head and I'm of the opinion that I don't have to be limited like that.
Now the thing is, if the arm and cartridge aren't up to snuff, the electronics won't do you a lot of good. I would therefore be considering upgrading the arm and cartridge first- but you do have to deal with the issue of how much output the cartridge has and how this might affect the preamp issue. FWIW, I've found that the ability of the arm to track the cartridge properly, combined with the ability of the arm to allow for absolutely correct setup of the cartridge, will trump the actual choice of cartridge almost every time.
To put that another way, you don't have to spend a lot on the cartridge if your arm has its ducks in a row. I know this will be met with some scorn, but I'm not kidding here. I run a Triplanar, which is one of the most adjustable arms made; one day I found that my cartridge had inexplicably lost a channel, so it went back to get fixed/replaced. In the meantime I was needing my fix of tunes and the only cartridge I had laying around was a $35.00 cartridge new in the box. I figured, 'why not', set it up with the same care I would a $8000.00 cartridge and see what happens. Well it tracked perfectly with no hint of stress on real torture tracks, but sounded a little up front (well, more than just a little...). But then I realized that it was a moving magnet and loading is a big deal with them, much more so than moving coils, so I experimented with loading and the up front quality went away: the cartridge was smooth, fast, detailed, extended- in fact the only real difference I could hear is that it obviously had more output so the noise floor was lower.
So you might take this into account with your update scenario.