FWIW, I measured the latency on my Epson 8345 (same as 8350, it would seem) running through a Sony HT-CT550 with RockBand 3 (the guitar having audio and optical sensors for measuring lag for calibration). The results for both audio were consistent between tests, and were in the range of 42-48ms. Well, actually, one was 42ms and one was 48ms, but I can't remember which was audio and which was video.
Either way, that's low enough lag, and close enough between audio and video, to be perfectly fine in my books.
This projector replaced my old 37" LG LCD television, which had originally been bought because it had the lowest latency of anything else on the market at the time, and the TV had more latency than this.