Just finished my install...and I used the following brass fitting from McMaster-Carr. It made it super simple under the hood.
44555k173 (Brass double barbed tube fitting, reducing tee for 1/4 x .170 x 1/4 tube ID)
I used it in combination with the following tubing: 5236k832 (High temperature silicone rubber tubing soft, 1/8 ID, 1/4 OD, 1/16 wall).
It fit the stock tubing perfect, and reduced down to a decent size to go straight into my boost gauge. I did have to get a reducer to screw to the back of my gauge, but I had those laying around. I love Mcmaster-Carr....it is super easy to find almost anything there.
I might add a picture of under-hood if anyone needs it.