I've had my Z since mid college days. Since about 1989 or so. It's the same Z only lots of money and mods have gone into it over the past...2006-1989= 17 years. I am a loyal person and seems like I owe the Z a good life. I have had three daily drivers parked next to the Z since about 1993. Each one was an improvement over the next as I established myself financially. First a used 1990 Civic (40K miles to 140K miles broke down twice), next a used 1996 240SX (55k miles to 110k miles, broke once), now a new 2002 Subaru WRX (0-80k miles not a hitch yet). All along, I was able to keep the Z and improve it a little at a time. When I bought it for $3500 with 69,000 original miles, I told the owner that if he ever saw it again, it would be better than it was that day. No, the Z can't do everything but it does a damn lot. It's cheap to own and easy to work on. Work on it if you want or just drive it. It's generally very, very, reliable.
My friend with a 1996 Twin Turbo Porsche AWD, drove my Z and calls it "the machine" He had a grin from ear to ear when driving my Z. You just can't get the same feel from a newer car.
In addition, don't be fooled, selling your Z is not really a profitable thing to do. In most cases, you might as well just keep it and use it on weekends for fun. The fun/money ratio is high in a Z.