i was told that also Tommy,i asked and they said it was "recommended due to manufacturing tolerances,spec something" i had no problems with the upper and lower stock and the aftermarket arms on my 9".oh well.my dad once said,"if it ain't broke,don't fix it"LS6 Tommy said:Robert1320 said:You'll need adjustable uppers if you go with the 9".
??? Mine was a direct bolt-in with stock suspension.
Tommy