If you are talking about the twin fan unit Byron F-15, you might want to go over what will be needed to make her ready to fly.
Couple that with the two power units to get set up and the other things associated with twins and you might want to wait on that for a later project.
If an F-15 is a possibility go with the TGA F-15, you will be glad you did.
I was just on their website www.tgajets.com and they have some fantastic Christmas specials on the F-15 and Mig-29.
Paul