This post possibly brings already known things (since it was discovered first by DexX 5 years ago), but there was no much information on this subject presented.
Since III/VC/SA use vehicle reflections, RW's 'Material Effects Plugin' material extension is exist in these games.
This section holds such effects like bump-mapping, environment mapping (ZM and Kam's scripts can export this, but with limitations), dual-texturing and uv-animating (which is not available in III (and maybe in VC too)).
I've created article about this section here
And created some tool for GTA3 (which works in same way as 2dfx tool) (it possibly won't work with VC because of different RW version, but I can update it for VC too if anyone is interested).
So, do you think there's any reason for creating special tools for this thing?
PS Also thanks to people from russian forums (Xepoman007, Zmey20009 and DimZet13).