Hales T5's Vifa's $ ohm or 6 ohm?

Sean is very explicit BUT, things aren't that complicated since: you've worked on the x-over so you know (or the modder should know) the tweeter schematic. You can test the existing tweeter(s) to get the parametres & impedance/ amplitude curves OR, simply, back-calculate the "ideal" tweeter parametres based on the tweet's cross-over...

The only thing you CANNOT do, I guess, is actually listen to a bunch of tweets to decide for yourself. Take a look at the LDSG for a few ideas. You don't need to hurry!!
Cheers.

Oooops just remembered the "killer" Vifa tweet fm their XT series. It's the 25TG30-04 (4 ohm, as indicated).

Mitchb - I have a pair of T-5's and would be interested in upgrading them as an alternative to buying new speakers. Let me know what you decide to do and how it has improved the overall sound. What are you hoping to achieve with the upgrades?

Gregm , The 25TG30-04 are too small physically for my speakers. I think they are 104mm and I need 110.4 to avoid major cabinet work. I went with the Seas Millenium as they are the correct size and I hear they are pretty good.
Dawgbyte, I upgraded my Hales T5's for the same reason you want to. I didn't want to buy new speakers and take a huge loss on the Hales. It was kind of the best of both worlds by upgrading the components. At least so far the crossover mods have been successful. I completely redid my crossovers and internal cabling of my Hales to expensive but appropriate parts with success but be careful if you mod your speakers as it is a gamble. Things could go wrong from what I'm hearing. I got lucky.

I took the plunge an installed the Seas Millenium about 20 hours ago. It is a nice improvement as far as I can hear. I don't know how it would read on a test but it sounds awesome. I'm excited and am not putting back the origional tweeters. These tweeters are beautiful. I cannot find any fault to them sonically or physically. They look cool too. They match my midrange drivers.