I have a '97, what issues are you experiencing with your Zf ?
My '85 BMW with the same Zf 4HP22 unit at 225K still runs great.
I hear peterschmidtransmission.com is a reputable, but expensive company, I contacted them about rebuilding my valve body last summer & they were twice the price of Jaggi in Houston.
If your problem in the valve body, you can send the body in the large USPS flat rate box for a hell of a lot less than UPS 3 day & have a tracking number.
If you decide to go the used route there's a great LR recycler in Rancho Cordova (near Sacramento) 3551 Recycle Rd
Rancho Cordova, CA 95742 (916-631-7744)