Had two 05 sedans, 08 G35X, and now a 04 coupe and 13 G37X
The 05's felt more sporty than the 08+ in my opinion.
08+ more luxury improvements.
Based on the Owner's Manual, you can run REGULAR gas in the 05 sedans but you should not in the 08+ sedans
However, some folks run regular regardless like Telcoman.
But, he is a seasoned driver driving a STICK that does not drive his sport sedan as a sport sedan.
In my opinion, you can possibly get by with regular based on meeting all three of the above criteria.
With that said, depends on what you want out of your driving experience and bank account!
