We all know that the 5.25" speakers don't make any Bass, at least anything that's audible at 70+ mph. Last year I installed a Hawgwired 2/150 amp and a pair of JL Audio 5.25" speakers on my CVO Roadglide and once again was disappointed. I took a chance and bought the BikeTronics 6.50" conversion kit. I installed it this weekend and I gotta tell ya , along with the Hawgwired amp I can finally hear some bass, or if I ain't hearing it, I'm feeling it. Simple kit to install, no cutting or anything like that, just install the adapters, mount the speakers, do a little wireing, worse part in removing/installing your fairing. Don't know what it would sound like without the amp.