Distortion from Audio Rack ??

I've appreciated good sound for many years but only recently have I been willing to invest the money needed to create a system I loved.  Granted, it's at the low end of high-end, but it is my high end :-).

Current system:  Advanced Paris A12 amp, EverySolo A10 streamer/DAC, Furman Elite 15 PFi power conditioner, Warfdale Elysian II speakers, SVS SB 1000 Pro sub, all cabling - Cardas Clear Reflection.  Room size - 24' x 14'.  Sounds amazing!  Sub will likely be upgraded within the next year.

The issue - my audio system is housed in a large wall unit made back in the mid 80s.  There is open cabinet space originally intended for either audio or TV.  Dimensions of available cabinet space - 23" H x 30" W.  My solution for housing the electronics was to purchase a Riveco 9U Rack with Reinforced Top.  I purchased a separate mid-level shelf connected at all four corners.  I also placed Pangea Audio Mega Feet under the rack.

I've read a lot on different forums about the impact of surrounding metal, vibration etc. on quality of audio sound.  My system sounds excellent and I have no complaints about "perceived" distortion.  But I also know from my own experience of upgrading cables that it's difficult to anticipate the degree of improvement one might find until you actually find it.  

So my question - do folks see the rack is problematic?  And besides getting rid of beautiful cherry wood wall unit, are there additional solutions within reach that don't entail a major restructuring in the placement of my electronics?