Not the same situation, but I also have recently very carefully debated, do I upgrade, or spend money on the airframe I have, Bonanza.
I have looked at 310R, because I really like them, Baron 58, newer Bonanza, and I have decided for the moment to stick with what I have got. And spend more money on her. Reason, better the devil you know at the moment.
God knows where fuel costs will go, god knows where airframe prices will bottom out. There is a reason so many airframes for sale at the moment, people cannot sell them, and a lot need to sell them, financially.
Yes, it may be a good time to buy, but purchase for all the right reasons, not for a whim. Mission profile when upgrading is so important.
There is s beautiful Baron 58 coming across my radar shortly. I know the owner, know the history, but the question I have to ask, is why????
