is it bad to mix housings, having two front housings or two rear housings?

s4 n/a

 

I believe they are both the same. I also checked the coolant flow in the FSM and the coolant passages appear to be the same as well.

 

On a turbo you can't mix and match because the rear housing has a coolant hole that routes into the intake manifold.

 

+2

 

I've never seen a "turbo" housing without the coolant passage. its true the rear housing routes through to the turbo but the front housing just hit a dead end against the intake manifold.

But, on a NA. you're good to go. same same

 

All turbo housings have the passages on both the front and rear.

The only time mixing and matching housings matters is for emissions passages. If you need to pass, you need to keep the housings in their proper location.

Oh, and try to keep the wear mark from the corner seal on the same side as the corner seal.