An '05 is carb'ed. Most people don't bother putting a high flow breather on until they've put a better flowing exhaust in place. You can install pipes/slip-ons without re-jetting the carb, but when you do both exhaust and intake, you'll want to re-jet.

 

With the stock back plate and lower Air scoop,,I doubt It
But then again Thats what I am gonna do,,I dont want to hear Intake
noise.
If the proper SE air kit gives 5 hp alone,,no exhaust mods,,
I'd bet Just the K&N filter element would net 2-3 hp,,,guesstimate only here.

Will you feel 2-3 hp more,,Are you an average rider who likes to yank on It
now and then,,,I doubt It,,
But maybe,,IF you alreay ride the bike for all Its worth.

Would half a stage one set up add a noticable power Increase,
Shure, But Barely.
Most get fooled by the louder sounds of Intake and exhuast.

Again,,A rider who already rides the bike for all Its worth will feel
even a plug cleaning,
or fresh gasoline,
or a cleaner air filter,
follow me ?

 

Here Is your best Bang for the Buck,,,
You get a little extra power you should be able to feel
In yer *** AND that Oh so sweet Harley sound XD

 

Hilarious add on to this thread. I pulled the air cleaner assembly off to install the chrome tappet block cover and found inside the stock box a K&N air filter. I bought the bike used and I guess the previous owner thought the K&N would turn it into a rocket.

Based on the feedback in here if I change out the air cleaner it will result in a style upgrade and not necessarily a performance upgrade. In the meantime I'll check out the 2 into 1 pipes.