I have an 07 SG, did the same thing, i like my tunes too.started with HD Boom audio, nice for a while, then went to J & M with a 250 watt amp. Much better sound, fuller and a bit more bass. Then I added fairing lowers with Fairing Factory 6.5 speaker pods and a new J&M wiring harness to run 4 speakers in series off the amp. Sounded much fuller but still not loud enough at speed.
Now I bit the bullet and went to Arc Audio 500 watt x 4 channel, 6.5 speakers in fairing and lowers and this thing will rock your socks off.
BTW I have my J&M stuff for sale in the classified.
There's no cure for dumb but it sure thins the herd