The old EV T350 is considered by many to be the best tweeter ever made. I have
a pair and I love them. They have big magnets and they are super efficient.They
can be too hot for some systems and will require an L-Pad or resistor to cut
them back. Problem is that their reputation has caused them to sell for up to
$900 a pair on E-Bay. The newer versions, ST350, sell for less because they
aren't "vintage" and they probably aren't quite as good. The EV T35's are OK
but have less output than the T350's. The old Altec 3000's and University
HF206's are nice and pretty efficient too, but they won't give as much SPL as
the T350's. For new tweeters, maybe TAD or Fostex?