Is Stock Power-System enough?

Try to be as descriptive as possible when posting.  You gave us the year/make/model number of the vehicle- that was good.  If you can give us information about the rest, it can allow us to better work with you.  Even if you don't have model numbers, if you can post some specs, that can sometimes be just as helpful.  One piece of equipment that will probably use the most power is one you didn't mention- your amplifier.  With the equipment you have described, I foresee no problem with the stock alternator, but depending on your amp (and maybe something else specific to your other equipment), you may need an upgrade. 

A good way to figure max system draw is to add up the fuse ratings of all your equipment.  Now, lookup your factory alternator output.  Then consider you also need enough to run your vehicles other accessories (maybe another 25-40 amps or so). 

$250 to $350 depending on where you buy. yes it is worth it. I could not live with out mine. Would you "wreck the stock alternator"? Well that depends on your defintion of wreck. Over load will cause premature failure, but to me the worst part is poor performance of the elc system. Just think about it. You are driving down the road, it's raining so you have your lights on , your wipers on, your a/c on, tv's on subs booming. that a big load.  Read the stickies above. Big 3 and all the others they will anwser your questions. good luck on your project.