I'd get the .65 also. I'm planning on doing the Hot Rod Power Tour this year & I'd rather get more than 9 mpg. If I can get 15 or 20 then the fuel savings alone will pay for part of the conversion. I'd love to do the Tremec swap but I'm afraid I wouldn't be able to afford to go on the Power Tour afterwards. Plus, similar to your new roof problem, I need a new heat & air system for my house. I guess if I spend all my time in the garage then I really don't need heat/AC, huh? Haha