Okay, since I only had one shim, I will leave that in. I ordered a pipe from ehobbies. I had a link to a page that explained grinding the opening with pictures but lost it in my many rc links. Anyway, I received my pipe today and as with all CEN parts, no instructions. Does anyone have this pipe? The nipple sticks straight out. It seems like a 90 degree nipple would work better. Did you change this?