System advice

My system is thus:

Vandersteen 2CE sigs
Anthem MCA 20 amp
Anthem TLP1 preamp/tuner
VPI Scout with Dynavector 10x5 and SDS
Audioquest Diamondback ICs
Denon dual deck CD player/recorder

I'm thinking about upgrading but I don't have any specific complaints about any particular component in my current setup. I do know it's lacking compared to higher end setups I have heard but again, nothing I can enumerate.
I have about $2k to spend.
Can you recommend any component replacement or tweak that would make a clear improvement for that amount? Thanks in advance.