The only difference is low end extension I am pretty sure. I chose to do the smaller studio version as I like the look of them more and really wanted to stay away from towers.
Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
That's right. The difference is entirely below 100Hz. The towers have greater extension. The standard bookshelf model is solid down to 65Hz, but the towers go almost an octave lower.
I personally like the bookshelf model when used for surrounds, and the towers when used in a stand-alone two-channel system.
Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
The full part number of the current production DX-25 tweeter is DX25TG-09/04, which as you've said replaced the Vifa DX25TG05-04. They're virtually identical, essentially a copy made at a different manufacturing plant.
The towers do provide a healthy dose of midbass "punch" and also more deep bass than you would probably expect from a 10" midwoofer. It's a very satisfying loudspeaker.
I've been very happy with solid-state and tube amps. I've personally run my two π towers with a 50 watt single-ended FET, a chip amp, a modern Harman-Kardon receiver, a single-ended 10 watt tube amp and an ultra-linear 10 watt push-pull tube amp. The towers present a benign impedance load and are fairly efficient so they can be run with pretty much any amp.