just like to share my experience with the fxdfse. I´ve ben A mc tech since 86. (Japanese dealer ship) mostly. any way the power comanders are widely used in the jap arena and there is a lot of support and maps for them harley not so much, I paid 300$ for a dyno tune, what a waist. it was so rich it was ridicules....I orderd a auto tune. wow. I love the technology we have today. anybody with any kind of mechanical background and a little common sense can be a pro home tuner. Now can anyone tell me the differences inside the top end of a fxdfse and a fxdf. thank you .