The waveguide in the 4430's was vastly inferior to my current one. The rest of the 4430 design is OK, but could be improved. I had once thought of just replacing the waveguide, but then I concluded that there were so many other things that I could try at the same time. I have often refered to the Summa as an updated 4430, which was itself an updated A7. The general concept (2-way, CD) is sound (pun intended) but we know so much more today and have so much better components. I am not a nastalgia fan, if you couldn't tell. Nostalgia is for old recordings not old equipment.