I want to keep my engine as stock as possible with no modifications like adding a Stage I kit or modifying the FI. Can any of the Screaming Eagle pipes Harley offers in their big book be installed without further modifications?
I think the big book has that information in it actually. I am pretty sure you can add the SE pipes (not SE II) without any other mods.
But dude, the Stage 1 kit is not "engine" work...it is just a better flowing air cleaner and freer flowing pipes. To deal with the extra air flow you get a FI reprogram to also up the fuel to match(reversable if you would ever really want to) or carb rejet. All you are doing is taking it to where it runs like it should without all the EPA choke-holds on it.
It's not like they're dropping new cams in or anything.