I did the heater first last December. My gen 1 soft doors leaked so bad, it was like I hadn’t installed a heater at all. Made the hard door decision easier though. When you put the heater in, spend some time sealing up the cab. The Honda OEM cab has a lot of air leakage that impacts the effectiveness of even a good heater. I used round pipe insulation for the larger gaps and Gorilla tape for small leaks. Made a big difference. I got a lot of good advice from forum members here.