There are two kinds of boost controllers, perhaps you are thinking of the other one?

In ball and spring kind, the ball keeps the boost pressure out of the wastegate based upon spring pressure.

The bleed kind is different, and I think with those it does not matter which end you mount each side of the hose on.- although, I don't know much about those!

I also have a controller coming soon, I'd like to know if you see any difference in spool up time...I'm excited!

__________________
Dan
2005 E320 CDI - 246k
1987 300SDL TD05-16g, Herlevi pump, Elbe manifold, 2.47 LSD - 213k
Past: 1987 300D - 264k