Hi Mark,You're going to have plenty of refined gusto in that amp when it's done. Very nice.
The E actually has its origins in the Snell E/II, not the D. When Snell decided to change the cabinet, Peter Q bought all the remaining old style cabinets, and later obtained permission to build more himself. The speaker has evolved quite a lot since that time, and is now available in two kits versions and 10 (count 'em!) ten finished product versions. (to say nothing of about twenty veneer choices, plus piano lacquer . . .)
The two kit versions (audionotekits.com) are available std (94) and high efficiency (nearly 98dB/w/m!). With your amp, I'd say you don't need the HiEff, unless your living room is the size of an airplane hanger! Knock down pre cut cabinet kits are available, if you prefer.
I can help you sort out the finished product versions, if you like. There are too many to go into as a broadside/sidebar here.
What else is in the system the amp will go into?
"I'm a strong believer in hearsay. I'll only say something about things I've actually heard."