Justin, Anthony and I have converted three older sabers. Mine with a 12lb and his with a P70. His was also NIB but an old verson. Mine had to be gutted and started over.
The conversion is pretty simple and straight forward. Call Patti and order the conversion kit with great instructions, new full size plans and cpnstruction photos. Follow the instructions and evrthing will work fine. We layed in some 80/20 carbon fiber in the rear section and nose section to strengthen the gear doors. Anthony also added 80/20 to the belly pan.
Be sure you strenghten the stabs by glassing with 1.4-3.0oz cloth, top and bottom.
Go ahead and order BV's belly tank and UAT. I would also strongly recommend using a full bypass. The bypass improves efficiency and protects the model in the event of flamage during startup and trust me it will happen.
Also, obviously try to keep it light, especially using a 12lb class turbine. I would eliminate gear doors.