You are worried about your cabling being susceptible to EMI, what would be the best choice if cost is not a factor?
Answer Description
Fiber is the most expensive cable type, but provides the fastest data speeds and is immune to electromagnetic interference.
Wikipedia
An optical fiber or optical fibre is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data rates) than electrical cables. Fibers are used instead …
Optical fiber - Wikipedia, the free encyclopedia