Towing the station wagon seems to be very hard. Trailer anchor points need to be adjusted probably. Haven't tested other models, but it's also the same for your Niva (both when towing it and when Niva has a trailer attached).

I'll check it out, towing is buggy af sometimes, is this with vanilla trailer or the modded ones?

I only used Better Towing mod that would affect towing, I guess. I only tried towing the station wagon itself with vanilla Mercia Lang.

Hmmm, that mod has a parking brake you have to disengage to tow, maybe check that

mod "85merc" not installed, cant join a server

that's a server/client problem, mod works fine, check the tutorials on pz discussion page for those problems

Is it intended that this car has the mechanics skill requirement of a performance car? i.e. mechanics 6 to work on suspension / brakes?

These vehicles always seem to spawn half-invisible for me in my SP game (i.e. only components visible), has this been reported/fixed for someone else before me? If so, how? Where should this go in the load order if that might fix the issue?

https://steamuserimages-a.akamaihd.net/ugc/10796779759607862/0EDF5EF1D27ADC20352E6DF95CA72D7CA947AD16/