Well I don't have this game, but I think in diskspan ([18] for custom) it should be something like this (latest UltraArc FULL folder is required):
Code:
bdt+pcars2_oo2reck+srep:m3f+LZMA-MT
But I have not tested and I don't know if the precompressor processes all files (even if they are not the target to go with this tools, like XTool do). But maybe this tool only works for the *.bff files (in this case use the UltraArc MASK method for the simpliest way to go).