Has anyone (HiFi , etc...) had any success addressing the severe wind shift while climbing through altitude?

You should look into the good work which Pete Dowson of FSUIPC4 fame has been doing in this area.His support forum is over at SimFlight ( http://forums.simflight.com/viewforum.php?f=54 )Jeff

Indeed, the new FSUIPC has greatly reduced wind shifts...At last, I can fly with XPax and not having my passengers screaming around the whole flight! :D :D :D

Yup, FSUIPC4 v4.25 and later (registered) has a lot of weather improvments including wind/temp/baro smoothing. The only outstanding known issue was the PMDG 744X could have some low-altitude course-following issues. Pete has raised the issue with PMDG and in the meantime, we just checked "Surpress Turbulance" on the "Wind" tab.Regards,