I am one who had a Z, installed a GTM TT kit on it myself and then a year later I sold it. Not for any reliability reason or because of problems with a shop.
Sometimes life just happens.
I started saving for FI as soon as I purchased my Z. I was single at the time and the word impractical didn't even enter my mindset.
Fast forward a year and I finally had the money to get a kit. Also, in the past year, I began dating a woman and it was getting serious.
I installed the kit and was having an absolute blast with the car. My girlfriends son was my co pilot and it was great.... Until the three of us wanted to go somewhere in the car. My girl would have to drive separate. We did that a few times to the local C&C.
Fast forward another year and girlfriend became wife. This in and of itself was not the demise of the Z.
My wife became pregnant and I mentioned that I should think about selling the Z. She immediately said that shouldn't sell it. Actually, she was very adamant that I not sell it. But the more I thought about it, it just didn't make sense to keep it. My time with the car would've been few and far between. The overall cost of the car could not justify keeping it.
For me it was an easy decision. I put it up for sale and it sold very quickly. (Probably should've asked more for it)
I do miss my car some but it has a new life with the new owner and he is very happy with the car. He's also done some things to it that were on my dream wish list. So it's kind of cool to see it with parts that I could only wish for.
I can't speak for anyone else but I honestly didn't expect to ever sell it. Life just happened and I made a decision based on what I felt was the best course of action.
Since I have sold the car I have let my mind wander and I have a bunch of different car related projects that I would like to do. I am not sure which one I will settle on but it's been fun trying to decide.