All new brace kits include everything needed to do a proper installation including inserts.
Per4mance Development 8-10mm Self Locking tool less inserts
Insert description: Inserts are for mid-2016 and newer cars that do not have threaded sections in the cross-member from the factory for either 8mm or 10mm bolts. Simply guide the insert into the existing slots of the cross-member and position for bolt insertion and tighten to spec with no tools!
