So what have I done to my car. A little before finishing running in the car, I had gotten a water temp and boost gauge installed into a carbon panel to the left of the meter cluster. Please note that this is a right-hand drive. One issue with the carbon panel was that it can reflect onto the window. The details are on another page. This is just me rambling.
The stock water temp is decorative, but doesn't do any good in determining how hot the system may be. I say 'system' because it is only one indicator. After starting and rolling the car for about 10 minutes, it almost always points 9 o'clock. If it ever even pointed slightly upwards, it could be too late. After getting used to it, I was able to know why the car felt sluggish or didn't pick up as expected in specific situations in retrospect.
Until 1998 the RX-7 didn't come with a boost pressure gauge. When it did, it replaced one of the useless ones. I'm sure I'm not the only one to have wondered why. Passengers would be able to feel when the driver was stepping or letting go of the accelerator, but for the dense folks the boost gauge is an irrefutable source of information. It also helps when running in. Many place their boost gauge right above the steering column.
The shop discouraged me, a beginner, from doing any hard tuning nor tinkering. They did emphasize cooling, which is why the above water temp was important. If I didn't know it was hot, I would much less be able to prevent myself from abusing the car unnecessarily.
What I did was change the brakepads and the fluid for that. I also had the the boost hose from the turbine to the intercooler changed to an aluminum one. Versions before 4 had problems where both hoses to and from the intercooler would crack. I'm talking about the accordion-like hoses. At a glance they look fine, but when you squeeze them you'd see it crack open on the side.