I pulled a pontoon boat and had a golf cart in the bed of my truck last weekend. It was not real windy nor was it very hot probly 70 deg f. My brother in law was pulling a 31' camper with his duramax:mad:. I was running about 12psi boost and 900 deg f on the exhaust pre turbo and couldn't get over 65 mph on flat ground without one of the two boost or egt's getting too the point I would get real worried. The boat was maybe 20' but nothing real heavy. I know I need an intercooler but is that really the best I should be able to do even without one?

I wouldn't think so. Especially with all the mods you have.