great info. +t. fwiw, doug never mentioned a difference. he knew there would be a brick involved and convinced us to skip the mods.
Look at it this way...
mics > m148(preamp) > 671mic in 671preamp > 671 a/d > cf
mics > m148 > line > a/d > cf
The weakest link would be the 671's stock preamp, stock is somewhat noisy, hence the Oade mod (along with other reasons). Even if it's modded, I'd still run m148 > line in (levels permitting).
Just the parts alone in the 148 cost about the same price as a pmd670... If only Doug was designing the preamp stage for tascam or marantz...
If you bought it from Doug I'd highly suggest the preamp mod, it sounds great, definitely worth every dollar.