[rustbucket]

Sounds like a heck of a lot of work! Should be a monster when it's done though.

How would you propose to circulate the water in the intercooler? That could be a problem.

Oil flow to the turbo will affect the lifespan of the turbo much more than the temperature of the charge. The intercooler is mostly used to keep the charge cooler. Cooler air=more power. Make sure you plan the lubrication system around the turbo. The intercooler can be an afterthought. A plumbing issue. ( I don't mean to minimize this issue, I just don't think its as important as lubrication).

Have you ever thought about putting in a hi-po T4? Could be built for about the same, if not less money than a turbo 1915. If you're sold on the turbo, why not a subaru conversion. Cheaper, already turbo'd.

I guess it really depends on what you're using for. What are your plans for the car?