I had J&M on my Ultra and just installed HogTunes on my new SG. My very unprofessional opinion is that the J&M's had a little more clarity, but the HogTunes have more bass. The HogTunes also have a tremendous warranty. I don't think you can go wrong with either, to be honest. They are both such a huge upgrade over stock.

If you really want to do it right, try this:

 

I changed mine to Hog Tunes for the Front, I will be adding the Rear Speakers and Amp later, I am Very Happy with the Improvement!

2008 Electra Glide Classic - Vivid Black

 

Infinity Kappa 52.9. Get em on ebay

 

Hogtunes. Great sound for the price.