Generally, so not directed at any specific supplier, the rack can have an ENORMOUS effect on the sound of the Neve module. In the 16 years I have been this side of the pond I have seen some regular horror stories masquerading as suitable racks.
I have a long post on my forums concerning grounding and how, for some bizarre reason, some rack constructors left it off completely. So a 2 core ac cord and plug and no ground at all going to the module. The somewhat distorted belief being this will prevent ground loops at the cost of the noise, stability and rf rejection of the Neve module.
Neve modules must be grounded... like the consoles they came from. If the studio is wired properly you won't get a ground loop as all the grounds should be at the same potential.
Next issue, the power supply. This should have sufficient current headroom to accommodate the inrush current of the capacitors charging and should also be exceptionally low noise because the power supply is part of the module's audio path and the module cannot be quieter than the power supply feeding it. Plus, if the power supply is inside the rack, the power transformer should not radiate such large emf that the transformers in the module can pick up.
Most importantly, electrical safety. Besides the grounding issue, I have seen racks with non-insulated ac connections and with ac connections perilously close to metalwork.
And finally, mechanical alignment to the module back connector and security of that back connector to the connector on the module.
If all these issues are taken into consideration, that's a great rack, but consider the points before buying one.
And don't forget, Neve modules never had a DI input, so what you see is the rack builder's adaptation of the wiring of the module.....