Why not make collision planes for DRS just like the Xsectors, instead of having to manually measure the distance from SF? Now the 32 bit version of rF2 is not working anymore, i can't use the plugin for measuring the exact distance from SF.
Plugin? Press Ctrl-H in devmode, it shows your lap distance live. Oh, and I would suspect having the zones defined in a text file allows for easier editing and potentially different zone positions for different versions.
