If it was me I would keep your 6.0 for now. Especially if it's a 05 to 07. There a better truck in my opinion. The 03 to 05 maybe not. I wouldn't worry that much on head studs especially if you don't tow much. Are you sure your not running too much coolant ? I would invest in a coolant pressure gauge which will tell you if you indeed have a head gasket leak.