10psi is rather high on turbos. remember, turbos make more boost than do blowers. i would run about 7psi which would be about 11-12psi on a blower. also, it would be intercooled so that would help.
i personally would buy the new instead of the rebuilt one, but thats just me.
to fab up the kit, youll need a ton of tubing. you could just turn the stock shorties around to use them as exhaust manifolds. i would buy the tubing because being off just 1mm can be very bad. there is someone who is selling all the custom tubing on 3.8 for about 1500-2000. that is a pretty good price IMO.
i would reverse the headers, put the turbine in a spot where the downpipe is easily accesable, then run the piping and IC that way too.
**I have sigs turned off, so if you're asking for advice based on your mods, I can't see them**