unfortunately almost all the shops i used to know around Chicago have closed down, the last decent place i remember was on north ave, near elston, but i forgot the name. More on reddit.com

Tip: Ignore the numbers on subs and amps that say "max power" or watts. RMS power is the amount an amp will push, and RMS is the normal amount that a sub can handle. For a daily driver, max numbers don't mean shit. Make sure your amp matches the sub in power output, then find out how to set the gains properly. I probably don't have to tell you this since you said you don't want overpowering bass, but NEVER use bass boost, not the one on the amp or the one on the head unit. If you set your gains properly, you won't need it, and it'd actually be bad for subs if used too much. If you don't want a lot of bass, but still want subwoofers, your best bet is either 1 @ 10", 1 @ 12", or 2 @ 8". Deciding among those options depends on how much you want to spend, and how much room you want the box to take up. More on reddit.com

QNX More on reddit.com

Local craigslist/kijiji will probably get it sold quickest. You will get low-balled quite a bit though. Other than that, Car Audio Classifieds .Org is a great site. My go-to site to by used gear. Downside is that I'm pretty sure you have to have a certain amount of posts before you can create your own For Sale thread. I guess it's a safety feature to keep most scammers away. More on reddit.com