Audio Refinement - NAD Cable request

Currently running the following:

PureAV Line Filter (forget model - $350 bought with BB gift certificate)
Denon DVD-3300 player
Audio Refinement Pre-2 (Cards p/c - forget model)
NAD S250 5 channel amp (Cardas p/c - forget model)
Audioquest Type 4+ shotgun/biwire
Wharfedale Diamond 8.4s

I bought enough Blue Jeans I/C cable to wire the whole setup and it is currently connecting my DVD-A player to pre amp and pre amp to power amp.

Although I'm sure my room placement is less than ideal, nothing can be done about it for the time being. The AR Pre-2 is a fairly recent addition to the system when my NAD S170 failed (and I was subsequently shafted and blamed for the failure by NAD).

My current gripe is the bass extension (lacking) and high frequency harshness. Some other issues such as placement and tweaking need to be worked on but I'm fairly certain the nasty highs are rooted somewhere in the speakers (number one suspect - I am not against ditching them) or the cables.
Do you have a buddy who can swap out your speakers or DVD player for you??? You need to do some comparison hearing....bass extension is influenced by very many things, expecially room placement