i am getting a system put into my xA and i have no idea where to start. What do i need, what kind of speakers and amps are the best, where to place them etc...
i don't want any ratteling sound

 

The rattling all depends on what your objective of a stereo system is. If you are looking to be heard for miles, rattle is almost inevitable. You can prevent most of it, but there will always be that one annoying buzz that occurs every so often, when you hit that one note! It's all due to resonation of certain components within your car. When they hit that "sweet spot" frequency, they rattle. Everything has its resonation frequency, all you can do is attempt to change the resonant frequency of more common sources of rattle with sound deadener. In my opinion, this is an early step in having a large stereo system. After all, if you've installed that wall of woofers, it is awfully difficult to remove it along with all the interior, seats, carpet, etc, to add Dynamat, eDead, BQuiet, etc..
I guess the best questions to ask are, "What do you think would be your ideal stereo system?" and "What is the main type of music that you intend on playing on this stereo system?"
If you are after the big BOOM that can crack concrete from a mile away and send soccer-moms into a tizzy at every stoplight, you can plan on spending a good deal of money. I suggest going to a decent stereo store, finding what you like, and then asking questions about certain products that grabbed your attention. There are quite a few knowledgeable users on this site that could certainly answer any questions you may have. Toss back a response to the two questions I asked, and we'll do our best to answer as best we can.