Inverter generators with exhaust extensions - feedback?

Venting out hot exhaust gas isn't your only issue as you must ensure the intake of fresh cool air that is directed at the genset. Don't do this and your Champ is sure to overheat and shut down. Opening the roll top cover is one solution but then what's the point in using an exhaust extension? Just leave the roll top in place, open the tailgate, and fan force cool air across the genset. Generator Line does offer genset exhaust extensions but AFAIK not for Champion gensets.