would increasing the size of the vaccum lines have any
benefit, performance wise... i was helping a friend install
a new turbo on his STI and it came with vaccum lines twice the
size as the originals. i was just wondering if doing this to
a suprchrgd engine would have any benefit?

It would have a negative effect. The vacuum actuated devices like the BCS and BCA would have a delay, as it would take longer (fractions of a second) to build vacuum in a larger line.

Ahhh!!! thank you sir...

on a semi related note i replaced all of my vacume lines with equivelant sized silicone hose. i had alot of small vaccum leaks in the old brittle rubber hoses and fittings. the silicone seems to make it run alot smoother and i think it will hold up over time better.
and being coloured as opposed to black it really spruces up the underhood area as well.
i grabbed the kit for like 15 bucks for a buttload of hose.

the only hose i had a problem with was the transmission modulator hose, the 90 degree bend at the bottom kept collapsing and causeing the transmission to shift funny. i've since replaced it with a formed 90 rubber peice.

Where did you find the formed rubber pieces (90* piece)? I was going to use norprene tubing for mine, but I think silicone is more easily available, and I may go with that.

well, i got the silicone hose kit from autozone. it was $15 and came with 10ft of the 4mm, 5 feet of the 6mm and 2 feet of the 10mm. it was availible in blue red and yellow. i went with blue.

i had a little bit of trouble with some of the fitting since they were different sizes on either end. in that case i used a number 10, 15 and 20 torx driver to slowly strech the hose until it fit the larger pipe. remeber guys, you've got to take your time and be gentle or she'll never let you do it again.
the trickiest part was the 10mm vacume line going to the brake booster, since the factory hose is larger on both ends, fortunatly the silicone can be streched gently and made to fit. again, be a gentleman or you'll end up with nothing here. i worried about some of the peices i forced working their way off so i secured them using small coloured zip ties.

the formed 90 i lucked out and it was included in with my new modulator. the original plan was to get a peice of 1/8 od copper tubing and bend it into a smooth radioused 90, then use silicone on either end to attach it to the modulator.

right now i'm looking into buying a small tubing bender and redoing all the hard plastic lines with a small diameter pipe, polishing it up with my buffer and clearcoating it.

Make sure when you buy new tubing that it'* rated for use in vacuum so it doesn't collapse on you under vacuum.

I used red polyethylene tubing myself as it has a more rigid wall structure and is rated for heat, pressure, and vacuum.

The stuff from autozone is made in China and is not pure silicone. that is why it is so cheap. I get mine from www.stylinmotors.com, wall thickness is much thicker and does not collapse at all. there stuff is great.