Some other 4.5 experiences along the way;
I have not biamped mine as I don't have a good enough quality amp to go with the Krell and I also never really thought there was a need with well over 1200 watts available into 4 ohms. It may well be useful so my lack of attempt reflects only my laziness.
The connectors are a bit of PITA, I have a pair of bridging connectors that seem to work just fine.
Interestingly a little old Pass F5 ran them at moderate volumes quite nicely while I had the Krell off being serviced which amazed me.
The EMIMs in the 4.5s seem to get a lot less rippling than the RS2.5s (or at least mine have) It seems to me to be a function of more drivers to spread the load - not sure how even the load is though across the 4 of them - I think the 1Bs have one driver carrying a great deal of the load. I swapped mine out (4.5 and 2.5) and set up Graz versions with stronger magnets and a spacing gasket - sounded even better. This may be due to more extrusion available and perhaps (Although I never noticed it in any case) the Bass-Mid hole is filled in a bit. I kept the pristine originals and have them stored just in case, along with lots of spare diaphragms, EMIM cases, tweeters etc; trouble is I have never needed them.
The Tweeters don't seem to have any problems and also look pristine. I have not yet checked capacitors
The Graz EMIMs also work a treat on the RS-2.5 and perhaps Graz ones in that application are even more useful as the standard ones really seem to take a beating
I also have the external crossover manual if anyone needs it.
Now all I have to do is get them out of their storage and fire them up again