Need help ...

Agree with Mward.  It's excellent equipment.  How does it sound to you?  If you like it, try not to obsess over whether it could be better and just enjoy it.

I agree with the two above comments, your equipment is very good.
Out of curiosity, what interconnects, speaker cables and power cords are you using?

I think you can squeeze a better sound from your system by using a better source component. Oppo is a good piece but a better transport combined with a quality DAC should be a noticeable improvement. This is of course a pure conjecture on my part since I don't have direct experience with your system.

I agree with kalali. I think that the Oppo is the weakest link.

Before you start spending money, make sure your set up and room are optimized.  If these are bad, you will just be throwing money away.