It has been said with a 97-03 GTP premium fuel is needed Is this true?
The owner's manual will list the answer to this question. Yes, you really do need to use premium (defined in the owner's manual as 91 octane or above) fuel in your GTP. This is because the higher output of the engine using the compressed air from the supercharger will be more prone to detonation (premature ignition of the air/fuel mixture) than a similar normally aspirated engine. Higher octane fuels prevent detonation and knock. In extreme cases you may use regular octanes, but do not do so for long. Hope this helps. G