Well, I guess you need to define for yourself what "sounds good," "runs cool," and "has balls" really means? Speaking for myself, I don't like what I think of as obnoxiously loud exhaust. For some, "sounds good" means the louder the better. I personally liked the way my Ultra sounded with the stock exhaust. I've got FuelMoto's Jackpots with quiet baffle on the bike now. It's a "little" louder than stock but mainly deeper in tone and I like it a lot but it's not going to rattle anyones windows when I ride by. On the temperature thing, they've been running hot for EPA reasons since 2007 or so. The 2010+ bikes especially so because of the catalyzed exhaust. If you leave the stock header, it's just something you'll have to live with. I put FuelMoto's stage 1 setup on my bike. It does run better from the SOTP dyno POV and I think it is cooler but get caught in traffic and it'll still get plenty warm down there. As for how the bike runs (has balls), it's a Harley. This is JMO but honestly, Harley's aren't fast bikes in the grand scheme of things, even those who have had a quite bit of engine work done. They run good and are very satisfying but there's plenty of bikes out there that will smoke em in any kind of serious race and without having thousands of $'s worth of engine work done first. Fortunately, they do seem to respond well to relative simple and inexpensive mods.
Money!! How much ya got??
I'm not familiar with Perfect Strom (did you mean "storm?") but I've read plenty on Kury and it's a pretty even split between those who swear by them and swear at them. The vast majority of accessories I've got are Harley stuff but I wouldn't totally swear off of a given add-on if it weren't Harley branded. I've seen some of Harley's stuff that wasn't that great. For example I put a Harley fuel door on my bike that had silver and gold flames on it. It looked really great for about four months before the gold coloring started wearing off. After that, it looked like c**p and it's no longer on my bike.
As for the engine mods, I like FuelMoto's stuff but there's plenty of vender's that offer quality products. All you can do is research and make a decision.
Good luck with yours!
Ride Safe,
Steve R.