Brian ask Erick a few questions like how much more HP/TQ the 181 makes over the 178. Also can factory belt be used with 181. I know he uses a fluid balancer in the wheel VS. standard rubber. As far as heat you are always turning the blower faster even at idle with the bigger pulley's , therefore you are always starting to make more heat. The question is at what heat level does it start to roll into the negitive gain area. Also what are the rpm tolerences for the blower from the factory, and what rpm are you achieving with the 181. My thoughts are if the 181 was free and easy horsepower, Renntech probably would have gone that route, I'm not a Renntech fan but the do have their roots from Mercedes so the knowledge should be there.