im not the most mechanically inclined, so i wanted to know the advantage of putting in a stillen air intake vs. leaving in the stock cai and any difference in aftermarket brands. any suggestions would be appreciated

 

Air intakes don't do much alone. You must optimize them in order for them to work properly.

 

Search the forums, use common sense, do a little research, here's a good place to start:

http://maxmods.dyndns.org/index.php?MaximaIntakes

And NmeMAX is right, proper tuning is what is really going to bring out the potential in an intake. Really proper tuning will bring out the best in anything, since all bolt-ons have to some degree an ability to be better since our cars stock were not designed for them.