I've never been that impressed with the stock stereo even though its the dsp set up its lacking bass im not talking window rattling bass just a bit more depth.
So I removed the stock subs and wired in an external Alpine amp and sub and im very happy its turned down as low as it goes and its perfect, takes up a little more room than I would have liked but I had the sub and amp kicking about in my shed so cost nothing.
The space issue isn't as bad as I've made it quick release.