I have downloaded the Y patch and can play it on SIngle Player.
When I hit Multiplayer and attempt to join a previously started track or even Start New Host I am only able to use the XF GTI and the XR GT. All the other cars including the new BMW are greyed out.
It just tells me that the host name I have initiated is "Host not displayed on Master Server"

It means your ports aren't opened, and you cannot open your own server.
You may be able to drive and all, but no one else can see it, nor join it.

This is nothing new to LFS.