No problem, we're all new at some point

Good is all in what you want to spend... For good quality, reasonably priced speakers (I'm guessing cost is a factor), check out the higher end speakers from Polk Audio, JL Audio, Infinity (essentially upper-end JBL), or Kenwood... Also check out the upper-middle range of speakers from MB Quart, Boston Acoustics and Alpine... All companies have a pretty full range of stuff, but the higher end speakers from the companies above are about equivalent to the upper mid range of the other three companies (which the higher end speakers go up to $1000 or higher)...
Sound dampening does just that... it insulates and helps to prevent flex and resonation of metal (trunk, doors, rear baffle, etc...), therefor helping reduce unwanted noise and keeping the energy of the speakers where it belongs (inside the vehicle). You do not cover the speaker, but any metal surface surrounding the speaker (generally the more you cover the better, but if you completely cover your doors and your rear baffle it's a great start).
Yes, you will have to take apart your doors... but it's pretty straight forward if you have a bit of patience and mechanical inclination... The biggest pain in the ass, however, is taking apart the rear baffle... Toyota, for some reason, decided to make that into a nightmare... So those of us with subs have to deal with a NASTY deck rattle that is VERY hard to fix...
The 1.5" speakers, while not true tweeters, are high-range speakers... They are located on top of the dash, just behind the front windshield to the far right and far left (by the pillars). If you remove the pillar trim pieces, I believe there is either one screw or a clip holding each cover down, then two screws holding each speaker.
Also keep in mind that there is a small, 4ch amplifier mounted behind your glove box near your cabin air-filter. If you swap your radio, remember to remove it (or at least by-pass it).
Let me know if you have any other questions.
-James