Welcome to the forum Molly!
I'd like to point out that there are limits to available amperage, with these things. If you want lots of bass, then you'll need lots of amps. That little engine probably won't generate enough 12v power for anything more than a good factory stereo. With any kind of amplifier added, you'll have to keep the engine running to keep the amp draw from draining the battery.
Facing the same problem, I went with a powered speaker from Walmart that's made for tailgating. Plenty of bass, and way more volume than you'll need. The best part is there's no wiring.
There's a similar problem with the lights, although not as critical since l.e.d. lights are typically lower amp draw than what we had back in the day, and certainly less than a stereo with lots of bass. You'll still need to check the amp draw on anything you plan to install.