Some answers:

- Can i use decal shadows in C-skript: Yes, with some restrictions, f.i. no individual decals.

- Imported textures are still 32 bit: Yes, for some reason unknown to me fixing this bug was difficult - it will be fixed in the next version, 7.7.

- Slow frame rate with OBB collision: Yes, OBB is slower than AABB, but normally there are many ways to get still a high frame rate. Upload your level or send it to Support and we'll check what can be done in your case.