Not to persuade the V8 conversion, but instead I went the Subaru route. Most don't think of this because not many have done it, and there are no "kits" for it yet. Cost a bit and required a lot of fabrication, but so far I am enjoying every second of it. Cost of motor parts are cheap and abundant, so not concerned about putting a ton of miles on it. I need to weigh it yet but believe it's close to 2000lbs. I don't have any track times on it yet, but will soon. Stock HP is 300.
http://forums.pelicanparts.com/porsche-911-technical-forum/488187-help-me-style-beat-up-old-912-a.html