Tweeter Setting 0db, -3db, -6db, Which?

im new to component speakers and using crossovers.. can anyone explain the difference in the tweeter ports. i assume they adjust the amount of bass into the tweeter, but unsure as which one to use.

No not the ammount of bass.  This changes how loud the tweters are.  0db is flat -3 db is -3 decibels and -6 is -6 decibels.  Install them and start at the zero setting.  If the highs seem to loud for your tastes go down to the -3 db setting, if you are still dont like how they sound try the -6 db setting.  It is really about personal preference.  just pick the setting you like the most.

ok cool. i just wasn't sure, haven't messed with Xovers before, as this is my 1st component install in my car.