Just so you guys know, my GT CHRA has a -6 water inlet/outlet. The kit that ATP sells for GT CHRA's has CNC'd aluminum -6 banjo's for use w/ -6 line. You could use a reducer and go higher than that for the lines going to it, but it's only going to flow through a -6 hole in the end. It should be plenty of water as that's what the turbo manufacturer and ATP (one of the highly respected race turbo companies) recommend.

The reason the heater pipes are so big is so that you can heat the entire cabin through a fan blowing through the heater core as quick as possible.

Joel Baldridge, ASE Certified Master Technician, Audi Certified Expert Technician