The Horseshoe Curve has been created for TS 2012 and TSX and is making good use of the latter at settings I use and have shown above.
It is some RW-2 routes which when run in RW-3 with TSX On that are suffering, some more than others.
You can test that yourself by running any route other than the HSC with TSX On and Off and see whether you can notice a marked difference in the display of the scenery, in particular the distant one.
O t t o