My bike's just a 97 Softail Custom, with the "mods" being a re-jetted CV carb with a Screamin' Eagle air cleaner, a Screamin' Eagle adjustable curve ignition module, and on my 4th exhaust setup since May of this year, lol...
When I first bought it, it had Vance & Hines 2.5" pipes on it, and I thought they were too big for a stock bike, plus didn't really like the sound for some reason, so I sold them.
Next was a stock setup, with crossover, and Screamin' Eagle slip-ons, which I thought helped the bike run pretty good.
Just for the heck of it, I swapped on the stock mufflers, but with the centers punched through with a 5/8" rod for a little sound. These actually felt like they made the bike run the best overall.
Anyway, looked around on Ebay and local Craigslist ads for a ThunderHeader and wound up scoring one off of Ebay for $102.50.

The seller said all they knew was that it was for a Softail style bike with EVO engine. According to the pics of Thunderheader's site, it was for an FL style bike, but I figured for as cheap as it was, I'd "make it work" if need be, lol...Didn't have to do anything wacky at all...bolted right on like it was meant for my FXSTC and not an FL.
Bottom Line:
Bike sounds badass...actually sounds alot meaner than it really is, lol. Has a nice deep tone, like a BIG BLOCK Chevy is the best way I can think to describe it. Feels like bottom end and midrange is slightly peppy-er than it was before, and top end, so far, feels much better. Overall just seems to be more responsive now, at all rpm's, and seems to rev quicker than ever... The sound is a little weird getting used to, and a bit LOUD, but I LIKE IT. It's not overly loud at cruising rpm's though. The performance is just an added bonus for me.
Very happy with the end result.
Extremely happy with the cash outlay for the setup, which was $150 for the header, the shipping, and two new exhaust gaskets.