You own an old car, just like all of us. Your car was assembled 11-12 years ago. A well-maintained VQ35HR on premium is already fast. The starting point is the maintenance schedule, another book with the owner’s manual. Get a complete list of Infiniti dealer services performed, it’s usually in their system. If the most recent major service, like 30, 60, 90, 120k, isn’t listed, get it done. In addition, the schedule runs out at 120k leaving plenty to do that isn’t in the schedule, such as spark plugs and suspension.

I just hit 120k miles, and did the complete premium maintenance list (found in the maintenance guide), radiator hoses & clamps, as well as passenger heater hoses (after a failure), spark plugs, struts (top mounts, spring isolators), shocks (top mounts, spring isolators), and front sway bar bushing (the source of a loud squeak). I also needed tires and will be getting a post-suspension alignment. This made a huge difference in the way the car drives.

Junior, how does the setup sound with the test pipes and muffler delete? Is it deep or raspy?

I agree with your logic Steve considering our cars are 10 years of age. I’m new here too but did the same with my z33 in the past and made a world of a difference especially on the track.