Hello Dinan_GT,
I think it is a waste of money if you are getting the same GT or even the LCI GT. The driving experience will just slightly change due to the newer version of N63.
IMHO your current car has enough power especially you have DINAN set up.
Maybe it's time for another model? X6m? LOL
Anyway a car will always be a car. It depreciates anyway.. You lose money here, and another loss for the new GT if you traded in.
If you love the car, you live with it, and enjoy it as much as you can. So touched with this guy, who appreciate his first M5
Once again, it is up to you to decide what to do.. CHEERS