differences between tweeters

As previous posts would show, i'm planning out my new system, so far i'm planning to run a 500 watt memphis mono amp, 2 adire audio tempest 15" 2 adire audio koda 8" in my doors, 2 memphis 6.5s in kick panels and now i'm down to picking a tweeter or component system, i'm really thinking about using diamond audios 6.5 components and skipping the memphis all together since its an all in one package, but i am stuck with what type of tweeters i want, i'm seeing aluminum, titanium and silk dome tweeters so i was wondering what the difference is between the 3 and what it will add to my sound stage overall, i listen to alot of metal and rock as well as rap so any suggestions would also be welcomed :).

J~

thanks for the link, that sums up most of my question :).

J~