Any way to reduce excessive road noise?

I have seen people take off the door trim panels and take up the carpeting and put down "sound deading" trim to dampen road noise.

I would think undercoating might solve or at least dampen the noise I hear from my wheel wells, including gravel coming up from the road hitting under the wheel wells and sounding like its contacting bare metal and chiming loudly inside the car. Really makes it feel cheap and tinny. Is this normal for Miatas? Any opinions on undercoating a Miata? Would it be gooping up things that are better left bare or might it add some nice sound insulation, if nothing else from road grit hitting the wheel wells? Maybe if just coated the interior surfaces of the wheel wells; Not sure I want to gum up the whole underneath or risk getting it on the muffler. Has anyone gone with undercoating, or just as importantly, does the car come with something to keep this from happening and maybe its been removed from mine? Thanks and best of luck!