My rig is strictly off road not a dd. Ram horns do have a place but are getting scarce and expensive, due to the popularity in limited classes of racing that don't allow headers. You can still find them on ebay and other on-line auctions but they can get pricey.
I do belive there is a definate performance advantage of the headers vs. normal log type manifolds. Any time you can get exhaust gases out of a motor quicker and more efficiently your going to make power even on a stock motor. Yes that is why so many people opt for after mkt or custom dual exhaust other than for sound.
Headers are not for everyone they do require some maintenance, But in my case that is a habit that is left over from my racing days. I do a nut and bolt check every ride or so on my rid just so i don't have any issues on trail and put me or anyone else in a bad way.
I'm certainly not trying to get into a pi$$ing contest with anyone and their beliefs, just an opinion on my part. I like my headers, so I guess i"ll keep them.