I suspect that for most modern houses, the difference between 175mph and 150mph is academic.
Agreed, only those dome homes look like they can stand up to that kind of wind.
Speaking last year about Dennis compared to Ivan, National Hurricane Center Director Max Mayfield said:
"the distinction between a 3 and a 4 should matter little to those in Dennis' path.
"It's a little bit like the difference between getting run over by an 18-wheeler and a freight train. Neither prospect is good," Mayfield said.
http://www.ohsep.louisiana.gov/newsrelated/DennisPoundsGulfArea.htm
Note, that was a 3 vs a 4, here we are looking at 4 vs 5.