Sorry guys, it was all misleading. The problem with CTDs on exiting 3D world persisted until I totally reinstalled TSHv3.03 from scratch. My basic TSHv2 install that I used as a platform for TSHv3 upgrade included different skins and textures and some custom files that I had assorted for TSHv2 mostly with Art Manager. I can't even remember now the details of all the custom files I used but they all worked fine in TSHv2 and looked nice.
Anyway, after reinstalling new TSH 3.03 (full TSH1, TSH2, TSH3 roadmap according to the latest manual), and using DXTweaker J I have not seen a single CTD. Messed with the new fresh install, game settings, drivers, and DXTweaker whole day yesterday, entered and tested different missions and didn't see a single crash. I'm very very happy with the stability, look and performance of TSHv3.03 + DXTweaker "J" on my HDD now.