Alot of questions there. The best thing I can do to help would be to give you this link...
http://www.mobileaudio.com/rac-faq/
Put on a pot of coffee, and start reading. Most of the answers you are looking for are in there.
You mentioned different mounting techniques and basically what is the best bang for the buck. There is no hard answer here. It depends on what you are looking for. Do yo want:
SPL (Sound Pressure Level) : Basically loud thumping bass
OR
SQ (Sound Quality) : Self Explainitory.
OR a mix of the 2?
Also, what kind of vehicle are you putting this into?, how big is your budget?, are you installing it yourself?, what is already in the car?
There are alot of factors to take into consideration when building a good system. Take some time to read some of the stuff at the link I posted, then give me some info as to what you are looking for and I will try to advise you as good as I can.
Hope this helps.....