As an owner of 5 Heresy spkrs with 4 more on the way: your 83 HIs are likely using H II components. Open them up. Check the xovers too. Unlikely to be type E. I have found the quality of the H Is to be far greater than the H IIs. The cabinetry is braced and constructed far better on the H Is. The drivers on the true mid 70s H Is are just like the KHorns and LaScalas (K77 and K55). The H IIs use different drivers - that look cheap by comparison. After recapping, my Is and IIs came closer together in overall sound quality and tone - but are not exact, though both sound nice :)
My goal is/was to get 5 good quality HIs and do a 5.2 system in the bedroom with them-with all matched innerds. Given all of the component changes over the years, it is painfully difficult to get matching cabinents and components. I have been at this since late spring. My luck might have been better with HIIs given what has been for sale this year. Lately I have bought 3 mystery Heresy's at good prices and 1 pair of HIs with very similar, though not exactly matching innerds should be here by Turkey Day. 1 speaker that arrived this weekend was from 1982 and despite what I expected, was filled with H II innerds in an HI cabinet. Oh well.
I have never heard HIIIs up against 2s or 1s. Most say they are great though. But I think the upgrade kit is quite expensive for what might be a modest gain or change in tonality in an inexpensive used speaker.
Just my 2 cents.....
Equip list: Main room: 75 N Khorns, 78 S Heresy Is, 79 T LaScalas, '93ish Academy centers X 2, '07 Madison Amps subs M1-218s x 2, '91ish Behringer B 1800x subs X 2. Bedroom: WF-34s; RSW-15 sub. New AV123 ELT525 5.1 system, sub eta late July 2009.
Amps: '64ish MC240s X 2 (PP tubes), '91ish Outlaw Audio 750 (SS).Sub amps: '07 Dayton 1000w X 2, '09 500w x1. 3 ?1980s Adcom amps, 535 2535, 555.
Also, main room: Outlaw 990 Preamp/Processor; '07 Oppo 981 DVD; Tascam Tape Decks (2) c. 2000; Technics Sl 1200 M3D turntable c. 2000, Stanton 505 and Ortofon OM NIGHT CLUB S cartridges. Homemade Audioquest interconnects (1/1, MAC-3 and MAC-6 wire, ITC 24 plugs). Sony KDS 3000 rear proj TV, 2008-does not cover over the 10' painting of my home, the French Quarter. Also, bedroom: Onkyo 805 rcvr; Sony BDP; JVC DVD/VCR, PS3.
Etc: MMF-5 TT, Bellari VP-129 tube phono preamp, Heresy IIs, c. 1985. Crites caps, 5/6 done. ALK Universals just finished. Trachorns here. Wooden LS horns and maybe Crites tweeters to follow. LSs may end up doing center channel duty.
Most importantly, my autographed picture of PWK himself. Listening to Jazz vinyl from the 50s-70s in stereo tube amp Khorn mode in the French Quarter former home of 1970s trumpeter Al Hirt - priceless