This very point has been discussed elsewhere,
http://www.audioaficionado.org/audio-research/23028-arc-coupling-capacitors-4.html
"Well,whilst I have no doubt that the recent ARC models IE; Ref75 ,Ref10, which appear to have never been supplied, and Pertinently, advertised with the ( 40 anniversary development ) White Teflon capacitors, will no doubt continue to impress and delight with superb sonics, those models were never Promoted and Marketed as supplied with Teflon capacitors, therefore all is well.
For my part what rather upsets me about this situation Is the Fact that ARC made a great deal of advertised promotional positive out of the Ref150 being supplied with said capacitors, as an integral part of the enhanced design of this model and It is the Ref150 With Teflon CC's that I spent no little time demo-ing in order to be completely sure in my mind of said purchase.
Having spent way too much time (than any sane person should) A/B ing most of the high quality PolyP, Film/ Foil and Teflon ( V-Cap, AuraT ) in my own re-build and DIY equipment, this point of component inclusion in the Ref150 formed an integral part in my considered selection of that model,when in reality I could probably have been well enough served, power output wise, by the Ref 75, at some cost saving to myself.
Had ARC, as per the fine print escape clause, supplied my Ref 150 with an like for like substitution of Teflon coupling capacitors then IMHO,
A, ARC would have complied with their duty of care toward their customer and B, I would have been content !
My sincere apologies to all fellow members exposed to this minor personal rant"