i've checked my brother's 2004 model
it's 21 mm & you're supposed to torque them down to 140 ft.lbs.
most newer vehicles are in metric sizes
best to get a 1/2" torque wrench and the proper socket to do the final tightening
and one of these would help speed up the process if you don't like air impact guns:
as a matter of fact, reading the measurements on the X wrench:
it's 17mm, 19mm, 21mm, 23mm
you may be thinking it's a 22 mm but those black plastic covers are just fo decoration, yo