Mach 460 lacking decent bass

[blesk]

I recently bought a 2002 GT with the Mach 460 sound system and the bass seems to be very sub-par. I've never needed to mess with the audio system in any vehicle I owned, and could use a lot of suggestions:

Is it pretty easy to add a subwoofer to the system?

I'd like to keep the stock look of the car and would prefer to not take up any more ot the already limited trunk space that the convertible model has. Is there a convenient place out of sight where I could place the subwoofer (and additional amp, if necessary?

What specific parts would you recommend? I'm trying not to spend too much money on it. Just need some halfway decent bass, nothing extreme.