[Vinny]

I have to disagree.You will notice a difference with just the filter and topless.It is snappier off the line,and better throttle response.The stock filter is made from paper.The K&N is a oiled cotten filter.It flows more air than a paper element.The more air you can get into the engine the more power it will make.Yes it will run leaner.
And yes you will need some kind of fuel richment device.

 

[Vinny]

I have the Turbotec pipes now.Before them was the Supertrapp V-5 pipes.
I did this when I had the stock pipes.no flash no PC or RT.It's really noticable down low in the rpm's.Itwas only mybe 1 or 2 hp.It gave it more throttle response.And a cool sound of rushing air being sucked in, when you snap open the throttle.

Yes,you will get alot more gains out of the filter with an EXHAUST.

I can tell you this about the V-mod muffler.I went to my old dealer(week ago) who sold me the bike,for a free oil change.And while talking a service guy.He said that my old ST setup is still the most power they got from a v-rod to that day.I dynoed at 113hp on their dyno.And he said the best v-mod mufflered v-rod got 109hp.Same dyno,same tuner.and he baselined at 102hp.That's 7 hp.Not bad,but not enough for me.