Like most anything electrical, you have to get over your fear of breaking something. Installing a car stereo is not rocket science. To be safe, disconnect the negative wire at the battery. This way you are much less likely to cause any shorts messing with wire.
Sub bass is incredibly easy in a car. people worry to much about subs. Even more than if amp a sounds like amp b and the ever popular which brand is best.
If you are doing it all yourself including building an enclosure you are going to need tools. Start researching some woodworking tools such as a skill saw/table saw clamps drill etc. Also wire strippers and cutters, screwdrivers and various other tools that you may need.
Vibration control. sounddeadenershowdown.com go there read up. Don is the guy who runs it. A super nice guy who will not steer you wrong, even if he has to send you to another seller for a better deal/product. Though, his stuff is top notch. Also regarding "dynamat" products "cld" Don recommends 25% coverage. After that you lose bang for the buck. Also a lot of that buzzing is the plastic panels in your car buzzing. Using some 1/8-1/4 closed cell foam as a barrier in between the panel and car sheet metal helps a ton.http://www.bcae1.com/
Go here and read up. A TON of great info.
A vehicle has a little gift from the audio gods called cabin gain. basically this is free bass below 80 hertz. Some have a lot (hatchbacks), some have less (vans large SUV's). So depending on your goals, you can utilize this cabin gain to your benefit.
If you run a sealed enclosure (recommended if you are building for the first time), even though the sealed sub may roll of (producing less output) at say 50 hertz, you are getting and increase in low frequencies that counteract this roll off. Look up cabin gain via google.
OK. Figure your budget. space requirements, and start looking for a sub. Stay away from the mainstream brands, kicker,JL, MTX, Rockford Fosgate etc. They are good brands. Just why pay for a name? Unless of course you have to have name brand bragging rights or they are on a killer sale. I of course like to kick name brand ass with not name brand product. Parts express has really good woofs. The dayton line is a sleeper. The HF and HO woofs rock. Phoenix Gold are often on sale at Amazon. Bought my son 4 P.G. RSdC 10" subs for 80 a piece. ridiculous output. Digital design, PAP or any number of brands are out there. Look up a decent car audio site.
Box building, If you want a ton of bass, look into porting, have the port tuning frequency 40-45 hertz. In car it will still reach mid 20's. Most music has little info below 30 hertz. The bigger the box the lower it will play and it is usually more efficient. Not always but generally. The trade off is finding what you can live with in box size and power needs and woofer requirements.
Hope this little bit helps.