alright, I'll do my best to answer your questions. I must say, these are some of the most intelligent questions I've ever heard on this forum, hahaha. In order...
1. I don't know anything about wastegates, I'll do some research and get back to you.
2. electric superchargers have been proven to be a wasteful draw on the alternator. I designed one myself a long time ago and scrapped it, because no matter how efficient I made it, it just wasn't worth it.
3. I suppose it doesn't HAVE to be... but much of it should be welded together to prevent air leaks, but if you have a way of taking care of that with plastic tubing, I'd be interested to see how it goes.
4. Yes, it needs support.
5. As long as the turbo you're using isn't too massive, you should be able to run it off of the stock oil pump.
6. It can come from wherever you want... just try to avoid the engine heat as much as possible, which usually means the bottom of the car.
7. Nope, don't know anything about it.
I doubt you'll find the answers to these questions on this forum. Try
www.clubgti.com/forum I'm sure you can find the answers there.