I built this on a fairly tight budget. All the equipment was from the used market and I have just a tick over 8k in it including room treatments. The only other item I would like to try if I can one at a good price would be a Levinson 380s pre-amp. But for now I am satisfied!
Your room is very nice looking and your system is well done. If you have a chance, checkout Audioquest Mont Blanc speaker cables (the best price/value combo in the AQ line IMHO) and Audioquest Columbia or Niagara interconnects. Other options include Tara The One and 0.8. I always liked the Infinity Sigma and Epsilon speaker offerings in years past; I'm sure this system must convey music in a very satisfying manner. You've done a great job squeezing value and great sound out of your budget. For a pre-amp, the 380s is a great contender; depending upon what sound you are after you may want to pickup a Classe DR-5 or DR-6 pre-amp or a later-model from Classe (CP-500). Enjoy!