I have a new condo unit that I love, but my next door "neighbor" is the HVAC/generator room, which contains the motor that heats the boiler for the complex. It is a 7500 RPM rattling motor bolted directly to the concrete floor that is shared with my unit.
Of course this produces notable noise and vibration which can be heard on my side of the wall. The sound is loudest on the wall of my livingroom, which faces the pump motor, but transmits as vibration to the entire unit.
I had a soundproofing contractor try to address the issue by foaming the wall and installing a layer of Z-channels with Quietrock sheet rock. Additionally, 2 triple lined fiberboard boxes were constructed and placed over: 1) the motor and 2) the constituent parts of the system. All of this has only reduced the sound to 50 dB inside the unit.

Additionally, vibration through the floorboards is still quite evident on my side of the wall. The HOA has promised to replace the noisy motor when the weather is warmer, but until that time, I need a better sound absorbing solution.
Some additional options I am considering:
1) Installing egg crate or other foam over the Quietrock wall interior to the pump side for additional sound dampening
2) Lining the motor box with soundproofing mat/foam
3) Having the replacement motor placed on a vibration mat to stop floor vibration (but this will not happen until the pump is replaced)
4) Having foam injection insulation placed in my midfloor (ceiling) to stop flanking noise (was considering doing this anyway to reduce ambient condo noise)
5) Possibly insulating the HVAC pipes?
Anyone have any further suggestions on this?? As a nurse, I am a bit out of my professional depth here...

Thanks!