Just recently put an RSD on the Bulldog Bagger, had to buy an S&S to CV carb adpator plate which I actually have an extra if you need one. You will also have to get longer head bolts I actually used bolts that a socket fits not allen screw head bolts and either make new spacers or do like I did and take some chrome washers the same size as the bigger part of the spacer that comes with RSD air cleaner and use them with the spacers that come with the RSD air cleaner.
The only thing that I can say that is either a pro or con is that you will hear this air filter sucking some air, almost like a huge air leak. But I'm guessing that is normal over the Big Dog stock breather. But I know since adding this my bike is running lean so when I get a chance I need to figure out how to go into pro tune software and change a setting that allows my unlocked VFI to self adjust all the time, not just run on the settings the shop put in it. So you'll have to retune carb if that is what you have or possibly retune vfi if its fuel injected.