Need cartridge advice

Get it rebuilt by Koetsu; don’t be the guy who makes another weird Frankenstein. I cringe when I see a Koetsu for sale with a ruby cantilever (always seemingly with "just" 5 hours since rebuild, lol), or with a mountain-of-glue stylus bond ala Benz or Van den Hul. And for $1700 you’d probably have to buy a used cart to match that level of quality, which is much more risky.

I’ve had 2 rebuilds done by Koetsu Japan now, and they come back absolutely good as new. Maybe better, depending how old it is. They seem to be VERY good and consistent with their current production. Always perfect channel balance. Often you will need a break-in period of 30-40 hours for them to sonically "blossom".

IF I were forced to consider a 3rd party, I’d contact Ana Mighty Sound, who seems to respect the original design and workmanship of a genuine Koetsu as much as possible. This includes an interface mount of stylus to boron cantilever with minimal glue; it looks very clean under magnification unlike other services. Going by their pics, it’s the only service that gives you something back that looks like a genuine Koetsu.

If you get your cartridge rebuilt by Koetsu it will retain value and you will be assured it will sound the same.

If you use a third party, have them replace with the same cantilever and stylus configuration it will sound about the same, maybe exactly, maybe a little different. If you decide to sell it you will take a hit on the resale price. The price for the third party work will be significantly less.

I don’t think there is a $1,700 cartridge on the market that you will be able to buy as a replacement, and think you have an equivalent or upgrade.

If I were planning to keep the Koetsu long term I would probably use a qualified third party for the rebuild.

1+ chakster 
I doubt you will get a better cartridge for $1,700. $4000 maybe.

Go for Koetsu official rebuild if you like this expensive cartridge.
Why not if it can be done by the manufacturer in Japan?

I have a Koetsu Goldline Black. Almost went for the Rosewood but someone familiar said the Black was awfully close. Whatever. Point is my Black is good enough I don't know what there'd be to replace it with for $1700. In other words even though that is a lot for a rebuild you probably wind up with a better cartridge than anything else you could do.

Rather than just send to Koetsu though I would at least make a phone call and ask Peter Ledermann the Soundsmith about it. He will probably be able to offer you options, some of which will make the Rosewood even better, save you some money, and for sure whether he says it or not will appreciate your business in these difficult times.  

Oh, and his Zephyr MIMC is the one cart close to your $1700 that might just be better than your Rosewood. https://www.sound-smith.com/cartridges/fixed-coil/zephyr-mimc-☆ While saving you a lot of time going without. I would ask him about that too.