If you have a 2nd car or can go without your current ride for 6+ months. I would say it’s not a bad time to sell. I always seem to be looking for the ‘next best thing’ and so I always wind up at a Carvana site or Carmax to see what the ‘baseline’ is if I were to sell it. Needless to say bc of the current market caused by the chip shortage - I can almost get what I paid for my Z; and considering it has 15k more miles than the last time I checked and I’ve owned it for 3yrs; I have considered it; but I know I will NEED a car afterwards and this one is paid off already so might as well enjoy it vs being on payments for a couple of years with a newer car.
Like you - I just got and installed the Z1 Intakes, the FI CBE and also the FI HFCs. I LOVE it except for the fake engine noise that needs to be disconnected (that is another story); so my advice would be 1. It doesn’t hurt to KNOW what your trade in value would be for Carmax/Carvana - and you can typically do it online, 2. Don’t put on the parts till you know what you want to do - bc selling new vs used - you’ll recoup the money you spent on them bc no wait time. 3. It sounds like you are a true car enthusiast so will you really want to be without a car waiting on something that might be delayed bc of the current market conditions etc?
Like someone said earlier - I think it would be best to wait a few years on the new Z - see what the reviews are like and see how different it is from the current Z. While I am excited about it - I just don’t like the idea of buying the first year of a car - even though it seems like most models go up every year by a little bit haha. Also I’m sure there will be ADM added to this car as well so it might be hard to find MSRP (gotta love the greed of dealerships)
Regardless - good luck