Thiel Owners

Dino - I believe the Dynaudio D28AF / 3.5 tweeter is no longer produced. Rob would have an idea of what best to do. We are looking for a long-term solution for that tweeter.

Regarding unsound's correct power information - there is often confusion between steady-state (RMS) and music-power requirements. US's notes all refer to amplifier requirements for musical program, which is transient in nature and therefore does not generate much heat in the voice coil. The huge majority of failures are caused by underpowering and driving the speaker with a clipped signal, which overheats and burns out the driver. The other failure mode is eventual fatigue of the voice coil leads due to long excursions during many years of service.  Someone on this forum mentioned a 7-year life-cycle, which seems reasonable if used vigorously.
Safest mode is a large power amp and reasonable listening levels - turn off if you hear distortion. My bridged DR9s produce 1200 watts into 2 ohms - I don't worry about burning out drivers.

Unsound

Thank you for the advise but at the moment I would keep as vintage as possible. I'll read anyway previous post on this issue. 

Tomthiel

To recap, you and Rob are diggin' in to find a solution for both tweeter and midrange. Great! I am staying still patiently waiting for any news here!!! 
You are right, I played loud (very much loud) in clip mode for some seconds, my Accuphase maybe does not like going that low (ohms)....
Has anybody ever had issue with the woofer, you know yesterday looking at the speakers I though it was a shame that a so well maintained pair of speakers was not working, there is letterally no scratch, no dent, nothing... but looking better with no grille... the midrange (both), It was like they just came from a "desert storm" campaign, they look like they are very, very used, but also looking at the ads on ebay or so they are the like, just do not fit with the other speakers and the beautiful wooden/black speaker. 
My woofer instead is really, I believe, like it was in the 90's, shining, the foam intact... just thinking out loud 
I love these speakers and I do not want to think to move on something different... I listen to a lot of speaker weekly, and the only decent one I would pick are Kharma, Martin Logan, B&W (not many...) Sonus Faber.... whose price is 100 times more the 3.5..... 

Dino - you may know that I had axed the 3.5 from my original short list upgrade program because of driver availability problems. However, through this thread and other investigations, I sense that the 3.5, along with the 2.4 are the strongest candidates for an AfterLife. So, they are now on our (Rob and my) radar. Eventually we will have a complete solution for them. Crossover tweaking must wait for replacement drivers, since upgrading crossovers for unavailable drivers is a futile exercise. I suggest that you try to limp along for now and that we will have more good news later.

@tomthiel, updates for the 3.5’s is outstanding news. Bravo!