I just wanted to share that I contacted Garret today regarding a Z3 HD and he responded quickly, answered all of my questions as such I too ordered one of his HDs.
My situation was different than most because I purchased the Pioneer Z2 update disk a year ago for my Z1 however never used it because I did create the the time to convert to the later by-pass system however with the advent of Z3's further updated maps this process made the most sense to me.
Thank you Garret
Shadowman