Of the ones that we sold (years ago), we consistently got the best results and comments from the D&D, LSR, and ThunderHeader pipes. That being said, it's my understanding that ThunderHeader has not kept up with the times, so the D&D and LSR would be my vote. The V&H ShortShots are not good pipes for most uses. If you are building a drag (only) bike, then drag pipes or other 2:2 are fine. For everything else, 2:1 is best.

 

There was a great article in American Iron a year or two back that really got ito the physics of short exhausts / long exhausts, two into ones and the whys and hows. Way more technical than I've seen in any other article about exhausts. In general if I am remembering correctly short exhausts with low back pressure offered better performance at the top end while longer pipes or pipes with more backpressure helped low end torque. Sounded though for a street bike it did not make enough difference to matter. That might be an oversimplication as there were a lot of other factors. Its just not the exhaust as the intake plays a big part.

Try searching for DYNO charts also. There are a fair number here. I know I posted mine somehere. I try finding the thread. and edit this post.

Her ya go:

https://www.hdforums.com/forum/sport...yno-sheet.html

 

Vance & Hines Staggered Shortshots. Top notch quality, jumped me up to 80 hp, and LOUD as hell.

 

Take a look at Supertrapp Supermeg 2 into 1's. Here's a link to dyno results;
http://www.nrhsperformance.com/tech_supertrapp.shtml.
They're tune-able for both loudness and performance. I've been told by two dyno operator's that Thunderheader's have a huge flat spot in the mid-range, although I never saw it in the bikes I've raced on drag strips that were equipped with them....but I'm just saying, do your home work.

 

If you can afford them, the Super Trapp pipe is the easiest to tune.