Turboman,
I dont believe the PDR hx-40 can be had with a 35 exhaust housing. I believe they say there is only about 75* difference in temp drop (200* vs 275*)between the PDR hx-35/16cm2 and the PDR hx40/16cm2 turbos. I'm going to change one out for a fellow TDR member so he can keep his pacbrake as well. He sent his (well actuall mine) stock 35 to Piers to be rework and them bought the 16cm2 housing. You can always call him to verify this. His number is 1-604-888-4159.
Nathan