I am surprised at what appears to be a big difference between "bit-perfect" digital data played on more or less the same kit. What is the physical conection between your G98 and G68?

However, if it sounds good, then it's probably ok. You have set up to send FLACs wirelessly to the Touch, to decode them to PCM in the Touch and send the PCM stream to the G68. That's all is it should be. If something were wrong, it would likely be obvious - eg dropouts. I can't account for the difference you are hearing, but if you have Accurate Rips and the Touch is sending bit perfect data, then I would say that that is what the files sound like.

MC200, Twinstore, 808v6/ID41 -> DSP8000SE (+ SB Touch, Sony BDP-3300, SKYHD, legacy cassette player)
2nd system: MC200 analogue out, Linn LP12, SB3 -> Quad 34 -> M60 rosewood
F80 (Rubino Micallizzato)
F80 (Rosso Corsa)