WOW ! Sorry, I mistakenly stated the MFI and SFI incorrectly, it was another motor situation I apologize.

OK the 3800 Series II and Series III,

L32 Supercharged
The L32 is a supercharged Series III. Introduced in 2004, the main differences between the L67 and the L32 is the L32's electronic throttle control, slightly improved cylinder head design, and updated Eaton supercharger, the Generation 5 M90. HP output is up to 260 hp in the Grand Prix GTP, though an inferior fuel supply system, and excessive torque management in the PCM, results in the 2004+.
Above was from a forum that covered the 3800 Series II and Series III motors. All I can say for fact is that I seen myself a huge difference in the series II and Series III motors. The Series III seemed to have a lot more power and with a high performance air filter on both engines the series III motor just ran a lot better. The PCM on the Series III even seemed to shift a lot better and all in all I feel the Series III motor was better in my opinion.

I agree, no need to argue over octane, that was NOT proper for me to be that harsh, I apologize again. BUT, I never had any issues on a acceleration when needed on the 2004 GTP, it would brake the tires loose easily and I still got over 25 MPG around town, over 30 MPG on the highway " on low octane fuel". Guess the
drive like a grandpa everyday??
in my case worked out, but sure would NOT suggest it for the normal younger person.

Good day !