I was told the 05 wheels were like the 04's (high positive offset +45). I had a time getting wheels for my wifes 04. Pontiac said the wheels were a 5x115 bolt pattern. All of the wheel mfg books I saw said the same. The wheels are actually a 5x120 pattern with that high positive offset. Check with http://www.tirerack.com They have wheels for the 05 and I'm sure they can tell you with certainty the proper offset.