Polk LSI series are great speakers. I have LSI-9's and they are excellent, but not real powerful on bass. LSI-15's have much better bass response. If you really crave bass, I have some ALS Platinums I could hook you up with, but shipping is next to impossible.
From my experience with both the C-1 and my current C-19 w/ C-9 sonic hologram unit I have heard no drop off in base response at all. The holography seems to put bass and drums center stage. Both have excellent phono inputs, though I prefer the phono on the C-19. Tubes do make a noticeable difference even though I use Silver 9T monoblocks.
Mobil Fidelity Sound Labs (MOFI) still cuts vinyl for the original tape studio master recordings. I believe Telarc does too. The MOFI recordings are excellent, as good as you can get on vinyl. They also do CD's recorded from the original master tapes.