Ok so I just got my 2004 wrx and my friend and I went to seafoam the engine. We took off a vacuum line and started then engine and poured the seafoam into the engine. Normally when we do this a little tiny bit of white smoke comes out the exhaust. However when we put it in my car it looked like a house fire. There was white smoke pouring out of the exhaust. The engine was incredibly dirty, took 2 cans of seafoam to get it to clean. it ran much much much smoother after doing this, I can barley tell the engine is on now. While putting in all the seafoam it threw a misfire code so we reset it with a code scanner. While we were in there we noticed the vacuum we running at 11 which seems low. I looked around and the norm seems to be 20. What I think is happening is that there is a vacuum leak that is causing outside unfiltered air to come into the engine. This would explain why the car was so incredibly dirty. As a side not white smoke not only came out of the exhaust but from all around the manifolds and turbo. I think it has some significant boost leeks and bad gaskets. I am wondering where to start looking for a vacuum leak and if it is ok to drive like this.