So, it says exactly what I'm trying to do. I'm trying to find a way to take Grabbing Style without dipping into Monk or Brawler levels. I'm building a grapple rogue, and I want to do this one without dipping.
Prerequisite(s): Improved Grapple; base attack bonus +6, brawler’s flurry class feature, or flurry of blows class feature.
There's a semi-colon after Improved Grapple, so you either need BAB +6 or any of the flurries to qualify. So lv 8 rogue is enough. Can even be taken with a ninja trick.