The DA40 in the US is a different kettle of fish. You can buy a DA40XL with powerflow exhaust which will cruise at 150 KTAS. I rent one regularly in Socal and it is wonderful to fly (especially with synthetic vision).
BUT I prefer to take the DA42 when flying in the SW USA. Firstly the turbulence can kick you around a bit in the desert in the summer and the DA42 is easier to fly and nicer to fly in those regions. If you get one with the 2.0 litre thierlet engines you are looking at a cruise of about 165KTAS which is ok, considering you are only burning 12 USG of fuel per hour (I know there is not meant to be any difference between the 1.7 and 2.0 engines but there appears to be a performance increase IMHE).
Plus the 42 has two engines. This I consider essential these days, last time I flew a DA40 down the Colorado river to Calexico, sitting over the desert 11,000 below, 100 miles from any civilization with just half a bottle of Gatorade and 41 degree C rocks below, I did feel a bit vulnerable.
If I could afford a DA42 I'd have one. It is a joy to fly, very comfortable, and I also like the stick.