So I ended up sending it, hooked the reader up to about 2-3 meters (6-9 feet) of wire, bought some JST connectors to go between the antenna + about 2 inches of wire and the rest of the wire. It reads perfectly fine, I was worried about nothing in the end! 
Full update coming soon, will likely do a new post in the Projects section once the whole thing is fitted in the car. Still working out ideal antenna locations and also waiting on some parts from AliExpress.