The 6-speed shouldn't be hard to switch over to. It uses a hydralic clutch, so linkage isn't required. While some modification my be required to mate the trans to an older Pontiac (or Olds 403), it shouldn't be that hard.

I wasn't sure what cost you were looking at. Obviously, the better the origianal car is, the less work required to finish the project. The aftermarket T-Top could be a problem if you need seals/weatherstrips or other related parts. I'd wait for the car to hit eBay to see if you could get it a little cheaper. If you want air, the compressor not being there could add a large expense.

My thought in regards to projects is to start with a solid body and worry about other stuff later. I personally have a hard time carving up a nice original. I bought my car as a roller without an engine or trans. The interior is trashed and two of the windows need to be replaced. But the body is solid.

I would think in most cases the project comes from what lands in your lap as opposed to saying I'm going to build this. The Stude was there at the wrong time, in the wrong place at the wrong price (damn, I had to buy it). I'm sure someone with money can say, "OK, this car is next", but I could say that.

While I did my planning on my computer, it was more of breaking the car down by sub-assembly in my 'bookmarks' for the internet. I keep track of different parts and companies I want or need stuff from. Stuff gets added all the time. Now my car is going to have more of a custom touch to it, so I have stuff from Classic Instruments, Ididit, Vintage Air, etc. Doing a car that you want stock with just a driveline change won't require nearly the same amount of changes.