Manley Labs offers a Mid/Side mod upgrade (vertical/lateral or sum/difference) to the Variable Mu® Limiter Compressor which opens the door to stereo encoding and decoding as well as exciting image enhancement processing capabilities. For instance, setting to compress only the in-phase information allows the augmentation of the stereo image as the out-of-phase content is left untouched. Or, conversely, if you need a "more-mono" mix for broadcast, or vinyl-cutting for instance, you can set it to kill off more of the out-of-phase info which leaves more in-phase material in the final result.
*Please note: you cannot have both the MS Mod option and High Pass Filter Option. You must pick one or the other.