It would be almost impossible to maintain that airplane. I've talked to people who were doing the TFE-731 conversion at Garrett LAX and from what I was told there is no SRM for the airplane and Lockheed isn't going be giving out Engineering Dispositions. Everything would have to be done referencing AC43.13 and it would get dicey with the FAA, or you could pay a DER everytime you needed to fix something structural, and you're probably going to be doing a lot of that on an old airplane that's been sitting outside for a long time. Pretty sure you could find some mid-time engines relatively cheap.