Just an opnion, but............. I'd tend to side with Glave on the exhaust issue. I'm not a follower....never have been....so I've never tried the Rineharts. Ran Thunderheader on my last three or four bikes and have been very pleased.
On an 89 Ultra Classic (head work, cam, air cleaner were only mods) I had the bike dynoed. Then went from dual exhaust to the Thunderheader and just the exhaust made so much difference.......I couldn't believe that just an exhaust change out could make that much difference. At that point, I could have become a salesman for Thunderheader.
On the SEEG, I decided to try something different and went with Vance & Hines Pro Pipe. While it is a little quieter than the Thunderheader (which is something that I was after in my old age), it seemed like it didn't perform quite as well as the Thunderheader. On this bike, with the mods being a SE High Flow Air Cleaner, Race Tuner and the Vance & Hines Pro Pipe my dyno sheet (posted on this site under the dyno thread) produced 101 horsepower and 104 lb. ft. of torque. I can't help but think that with a Thunderheader, I'd have saw those numbers just a tad bit higher.
As a side note, read the latest issue of American Rider (probably the Oct. issue) magazine. They have several articles and comments on the 103" motor and one pertains to the exhaust of dual vs. 2 into 1. I've said it all along, if you want performance, go with the 2 into 1. If you want the dual look, you can always go with the falsie left side like Thunderheader now produces.
Just my .02 worth guys.