The 2.2 911T is 125hp, by comparison, the 2.7 RS spec engine mentioned above is 210. I don't know how much you spent on the rebuild, but magnesium case engines, done right, are pretty expensive. So I won't get into the cost.
Putting the six where you had a four is alot of aggravation. And you're doing it for just 125 hp. Hmmm. Think that one over carefully.
The engine/trans combo are longer than the four. Can't go any more to the rear, so obviously you have to make clearance at the rear firewall. I don't know how much clearance you have know, but a 915 will take it all up and more, a little less space for a 901. I'm guessing you're going to grab the 911 'banana' trailing arms to bring your brake and axle system over intact. The axle length is pretty easy to alter.
I too find myself very trusting of the 911 engine. Especially after I saw the bottom of our 3.0 with 150,000 on the odometer. Looked new. 15,000 mile valve adjustments are nice.
When done, if done well, your car will be exquisite. Smooth, powerful and run a quarter million miles before overhaul. It will be amazing.
But you will no get your money out of it anytime soon. You will spend more money doing this well than you can recoup given additive costs of the original car, cost of fabrication, labor cost (even "free" labor you provide has a value), engine/trans cost etc...
Don't build it for resale. Build it because you want to.
angela