MR Ballard

I have a wren 54 MK2 Kit it has not been run since I built it some years ago. I will need another for my f-14, I see that the 54 has been changed/upgraded what would be my best course of action? purchase another at the current level and upgrade what I have or purchase two new engines? Can I get upgrades? which I prefer. I have experience with turbines and I like to do my own building. Can I get all information along these lines to aid in my decision?

thank you in advance....................DONNY