Benchmark Preamps and Amp - For real?

Jetter, At that money these amps are a huge bargain. You won't get anything better until Parasound releases a new JC1 and that will go for over 10K/pr

I was looking at a ABH2. Instead I think I'm going to try Class D PS Audio Stellar M700 monos. 

I listened to the HPA4 at Axpona this year while auditioning headphones.  I now have an HPA4 in my home system, as it paired astonishingly well with the Audeze headphones.  It is dead quiet and just gets out of the way.  Great bass extension and clarity.  I got it to be my headphone amp, but it also ended up taking the place of my tube preamp (in front of 300b monoblocks).  The tube pre has a little more bloom and spatial sound to it, but you really have to pay attention to notice.  What was more apparent to me was the absence of a subtle distortion in the tube preamp that I did not know was there until the HPA4 did not manifest that same distortion. 
Get it with the remote control - it is absolutely worth the extra $100 at that point. 

I have an DAC3L/LA4/AHB2 setup, and it sounds phenomenal.  More clarity than I've ever had before.  Speakers are Salk Silk Monitors with a Hsu ULS15 sub.  

DAC3HGC/AHB2 (no pre) with Joseph Audio Pulsars - definite synergy there with great definition and deep, wide image. Having not heard the pre-amp, it is not a priority for me right now.

I think the extra money spent on excellent cables is probably a better investment. (Nordost is best in this system IMO, have tried mid-range AQ and Shunyata also.) Can an extra piece of equipment improve the sound of the source - in this case the DAC3?

Compared with the Rega Osiris in place of the AHB2: I believe it is a matter of personal taste, but I preferred the AHB2 for its blacker background and tighter bass to the Osiris with its incredible dynamics.