i was running q, but only updated everything but the exe to patch T, i then played it and i had access to Aston GT & Aston North, so does this mean any smx file in the lfs dir will work?
The FO8's new dash is also available in Q and I'd imagine the BF1 is too if you update everything but the exe. However, because of changes in the exe, cars have bits which don't work eg gauges. So yes, things that shouldn't be there can be accessed but it doesn't mean it's going to work or be a good idea/stable.
You're not implying that it might be possible to add custom tracks to LFS by adding SMX files and then somehow being able to select it from the game..
It would probably be extremely unlikely to work as LFS is not finished and isn't designed at the moment to be modded in any way by users (I think). Don't go breaking your LFS now, eh