So, I'm thinking about going Turbo... Questions

[Focus_Sh1ft]

First off I'd like to say that I'm pretty new to car modifications so feel free to call me crazy for even thinking about doing this.

I love my Yaris, but I'm looking for more power... without drastically decreasing engine longevity and fuel economy. Bolt-on mods aren't going to cut it, and superchargers are out of my price range. Plus, I'd like the satisfaction of putting together a custom kit

After my initial research, I've decided I would like to aim for approximately 140 hp and no more than a 6psi boost (if this is even possible.. seems like it is). I would really like to keep as much stock as possible.

So here are my first set of questions:

1). So far, the Garrett GT25r and Turbonetics T3 seems to be the most approriate choices. The GT25 spools up at about 2000 rpm apparently, which would be great for a daily driver such as myself. Both of these are a bit steep though, and I can't find a used one on ebay. Are there any cheaper alternatives that spool up somewhat quickly? Would the Garrett GT22 work?
Also - pros + cons of internal v. external wastegate?

2). A log manifold is definitely my first choice for manifold. It should be approriate for the set up I'm aiming for, correct? It would be great if someone could supply me with some specs for the manifold as well.

3). Found the answer.

4). What other parts of a turbo kit can I do without (at low boost)? I was reading somewhere that a BOV isn't really necessary, among others.

5). Fuel Management - will stock injectors and a stock pump work at low boost? Do I need a piggyback system such as the GReddy E-manage?

6). Will I need a sump for feeding the oil?

7). How important is tuning going to be if I'm able to keep almost everything stock, and simply add a piggyback system if necessary?