CoiL
Member of the Trade: Wood Audio Accessories & Modifications
Only 2nd gen ATE FF-mod
On details as well? I tried open back ATEs back then I wasn't really that impressed(Great but not really that much "Better", different is the right word to use for my case) but then again I don't have the same setup as yours, I got 2 pairs this time probably will try the FF-mod on 1 pair, and depending my impressions I may as well stock 5-6 pairs for future proofing at 4$ xD.
I don't know what to except with ATRs, ATE had a really pleasant sound signature, buttery smooth and forward mids were their pros as I remember them.
P.S FF-mod as open back hole, don't have the option to use wood.
Well, if You remember about my FF-mod, then it wasn`t mainly about making them open back (which had minor effect) or closing port holes but whole new nozzle from ED9 (brass) - that has the main effect about highs and details
Btw, took a pic from my ATR mod: