my dad is looking at turbos and found a couple of hx40w's I think he said and was wondering how good they were?

 

There are a lot of things to factor in here. The 40's are good decent turbos but so are the stock one's. IMO.until you go much over stock power range. Who's hx40 are you looking at? You will get more air flow from the 40 but the ? is what are you intending to do and how much power are looking to run?

 

in reality he is looking to get a set of turbos to build a twin turbo 502