I have 2012 ultra limited with 103. This bike runs and pulls better than the 2010 103 that I had in the past. I am pleased with it and like the fuel mileage. However in the past I have pulled a trailer behind my bikes. I have not yet pulled with this bike. What engine mods would be recommended to get more pulling power out of the 103. I am not looking for big power that drains the gas tank. I take trips that are 4 to 5 days long at a time and sometimes over a week long. What's your experience on this.

I have had mostly goldwings over the years and they are somewhere around 40 hp more,so I'm used to that. I have heard others say the same as you about the small HD engines. I have no hands on experience with them,but from reading forums like these I have reached a conclusion that your bike just might pull better than my 103 due to the way the 103 is geared. I worked with a guy the moved from a 96 C.I. Bike to a newer 103 and he claimed the 96 would pull much better than the 103. He also thought the 103 was geared to high. My last 103 2010 ultra was terrible pulling a trailer. 4 gear on interstate hammering hard on the throttle to hold speed limit and get 26 mpg.. This 2012 is a much better and more powerful bike ,but I have not pulled a trailer yet.its get 46 mpg 2 up with luggage packed and a top bag running interstate speeds.

Stock 103 with slip ons and an FP3 pulls just fine. The only time I noticed it being sluggish is at high altitudes going up mountains in Colorado, but my wife’s 96” did the same thing not pulling a trailer.

You will be fine with out modifications, but your fuel mileage will suffer when pulling.