Should work, I would go with the bigger exhaust, I have no idea what would use a 6cm housing!

The smaller hx35 uses a 12 or 9cm exhaust housing.

 

The H1D auction fell through ; I was gonna buy one anyway because they were so damn cheap (50 pounds).

Anyway—found and bought a WH1E but I will need a smaller exhaust (it's a twin scroll 18cm).

Anybody want to sell me a 12cm housing out there? Or a 9cm too. Will need to be shipped to Italy, USPS preferred.

 

A 12cm housing won't fit without modification. The 12cm fits the smaller H1c or HX35 turbine wheel. The H1E and Hx40 usually use the same turbine wheel. You can get the BEP housing, which is pretty small but if you are willing to run high boost can still make a lot of power.
Otherwise I think a 16cm housing is the smallest size stock holset housing I've seen that will fit that turbine wheel without modification.

 

Ah well, there I have it. I guess I can always block off one hole.

I'm on good terms with a good machine shop so I could have one machined to fit the H1E wheel. I wonder if it would become too thin and crack though.

 

A TD05H 14b haha!

 

It can be done. A friend had a 12cm machined out to fit an HX40.