This is fix for excessive reflection of C7R diffuser when using non-static reflection setting. (This does not happen with static reflection.)
Install: Just drop the .dds file into your each C7R skin folder. (e.g.\cars\ks_corvette_c7r\skins\0_racing_3)
Make sure to backup original file in case you don't like it.
less reflective diffuser for C7R 2017-07-09
Fix for excessive reflection of C7R diffuser