I bought a couple of sets of Pontiac Firebird GTA wheel center caps for about 60-65 dollars for a set of 4 brand new to run on my 87 limited, so as not to risk loss/theft of the original T centers. If you google 87-92 Pontiac Firebird center caps for sale, many vendors have these available. You can get them in black or chrome plastic. They will have the Firebird design on them, but you can buy the inlays from several Buick suppliers(although they cost about as much as the caps). I did use some clear silicone caulk to keep them secure.