I bought a STI up pipe to go on my 2002 WRX. I have not put it on yet, but I have a gasket question before I do. I bought a gasket set online from Daddyssccp. The up pipe to turbo only has 3 holes to go over 3 of the 5 studs. I think this may be correct due to the wittness line on the up pipe I bought looks the same. There would have to be a recess on the turbo to match this however. I have a picture I can email, I am not registered with any of the image hosting services. I just don't want to get it apart and have to make an emergency run to the dealer for a gasket.
Just make sure the hole is centered over the pipe. That is how you know that you have it on correctly. You are correct, it only goes through three holes. I think it even sticks out the side.
I thought this was a really important gasket without which you could have a leak. I read on NASIOC that the pre turbo leaks were dangerous. True or internet myth?
I personally would NOT run without a gasket but know a few that are not using one tho. Maybe they will speak up with their experiences.