I have the tips, no HP gain, you only need a Power Commander or Cobra Fuel Management if you have open air covers, like a Duck's Mod. I cut my own filter bowl with a dremel ut some K&N Filters in there and it sounds awesome. Nice and quiet when rolling through the neighborhood, but when I REV it.:drool::drool:
For the money it changes the look and sound of the bike. Makes the bike even more noticable and people stare more. Not much in HP for the tips, but when you do the aircleaners it wakes the bike up.
The tips are way louder than stock but in a good way. You wont be disappointed if you put them on.
You really didn't lose HP but you changed the torque curve up higher in the RPM scale due to the lower backpressure. On my bike I did pickup additional HP but it is higher in the rpm scale and throttle response is better to boot. Also be aware that when you start changing things quite often you need to do other adjustments to make things work even more harmoniously and get the most out of those changes.
We did a dyno run on these when we first introduced. Got between 3-6 HP increase. Your results may vary. Honestly, not going to feel much without an intake mod to let it all breath. Then you should add a PC.