New preamp or other suggestions?

I'm really getting tired of the harsh sound of my system. At this point, I honestly would rather listen to music in my car than in my listening room. I've always chalked it up to a poor room layout (and that's not something that I can change), because this same system sounded UNBELIEVABLE in the dealer's showroom. For what it's worth, I've already treated the room with Echobusters panels, which helped quite a bit, but not enough to make the system sound really enjoyable.

Recently an audiophile friend suggested that a good tube pre might make the system more listenable. The current system is:

Source 1: CAL Icon MKII HDCD w/PowerBoss power supply
Source 2: Music Hall Fidelity CD-25 (stock)
Pre - Bryston BP-20 line stage (balanced to pwr amp)
Power - Bryston 4BST
Speakers - Thiel 3.6
Interconnect (pre to pwr, bal)-AQ Lapis or Nordost Red Dawn
Interconnect (CD to pre) - AQ Lapis, unbalanced
Spkr Cable - AQ Midnite X3

The system on the whole is currently lacking mid-bass (the terrible room strikes again) and has a harsh, in-your-face high end. Of the two sources, the CAL has a MUCH better bottom end, but is lacking detail and air at the top, and has a very "forward" presentation. The CD-25 has a much more detailed (and enjoyable) top and a wider soundstage, but light bass.

I listen mostly to pop, acoustic jazz and contemporary electric jazz.

My friend suggested picking up a used AR or CJ tube pre in place of the Bryston. Another friend suggested replacing the op-amps in the CD-25 with 627's to enhance its bottom end.

I'm a musician and not an audiophle, so I don't know if the advice I've received will fix the problem.... I'm also on a budget, but could swing $1-1.5K on a new/used pre if that would fix my problem.

Do any of you experts (and I mean that sincerely) have any ideas?