We've manufactured what I believe to be the most reliable slider hub available today.  In fact, it's guaranteed for 100K miles.

https://www.thesamba.com/vw/gallery/pix/1664118.jpg

In the Northwest, I'd take it to German Transaxle (unless you can get Tom Lengyel to do it).

 From:    Stuart MacMillan
 <stuartmacm@GMAIL.COM>
 Subject: Re: best rebuilt transmission
 
 Personally, I would not entrust a
 Syncro box to anyone who is not =
 experienced with them. Research
 carefully!
 
 Stuart