On an 01 any way the break booster line goes to the back of the intake. The pvc line goes in the middle at the top of the intake. I used the seafoam spray it comes with a u shaped tube so you can shoot it in through the TB by inserting the tube between the rubber duct, and the TB.
So I did all three locations. Through TB, PVC, and Brake booster lines. If you look at how the intake manifold is made there are a lot of nookes, a crannys for carbon to build up. I don't really think using one location to SF is going to give you the best treatment.
I thought something like that might be the case. Thanks so much for clearing that up!