noob stereo question, need help please! Options

[m0dd3d1]

So quick question guys, I'm looking at getting new speakers and a new head unit for my car and I was just wondering:

1 Are the front speakers on the door the same size/type/whatever as the ones in the back?
2 If I just get a good head unit (nothing special) and 4 new speakers along with new tweeters, will I need to do something about more power for them? How do I tell what I need to look for to make sure nothing gets overloaded?
3 If I get a double-din head unit like a screen, is that going to draw more power and cause issues if I don't somehow upgrade my power?


Thanks guys. I need all the help I can get, I know nothing about stereos.

[Redline08]

trust me get a sub and amp before anythign, subs add the best sound IMO. Sometimes when my cars not on i turn off my amp and subs to save my battery and the sound is soooo much different, just imo get a sub and amp for it first!