Thanks for the replys. I'm looking at buying a 300 for personal use and a lot of them use the oil cooler for heat. I was really impressed with the muffler heater I had on my r22. I try to limit myself to not flying in temperatures below 0 degrees fahrenheit. It sounds like I may need to wear long john underwear, choppers on my hands, pacs on my feet and a mad bomber hat to keep warm.