Bob,
I would inquire with a local driveline shop that does half shaft swaps, they have access to high quality joints and the different shim thickness that are needed to ensure that the shafts stay balanced. I only recommend this because I ruined the balance on my last set (there is a thread about that somewhere), however there are many people here that have replaced the joints themselves and never had an issue.
I assume your half shafts have 4 bolts that connect to the back of the rear hub and 4 that connect to a companion shaft that goes into the differential.
There are well documented CV swaps that you can do it's probably better to seek out those threads and see the experience of others, searching this website, zhome, and HybridZ would be a good place to start.
http://www.zhome.com/ZCMnL/tech/rearend.html
https://forums.hybridz.org/topic/103344-280zxt-stub-axle-cv-swap/
Or search with your wallet https://www.zcarblog.com/2018/06/08/performance/parts-z-car-garage-cv-axles.html $1600
What kind of Z do you have? CVs be smoother if you have a early setup with the diffs that are close to the front of the car.