If you can, do it. With the factory flywheel I did have to feather the throttle on upshifts to match the RPM. When you’re accelerating, it’s better to be a little high on the engine RPM than low, but as close as possible is best.
Down shifting generally results in a lot more wear, so I would definitely recommend rev matching while downshifting. I usually give the throttle a good quick deep stab to bring the RPMs up quickly, especially when skipping gears.
If I’m passing someone on a two lane road, I know if I shift from 6th at 2000 RPM to 3rd, I need to bring it up to just over 4000 RPM prior to releasing the clutch and mashing the throttle. The rev-matching is far faster than using the clutch to bring the engine up to that speed, and the car doesn’t lose much momentum in the process, making the pass much easier and quicker.
As for the power, don’t be afraid to rev it when you need it. For general non-highway cruising, I generally hold about 2000 RPM, more for hills, less for very low load conditions. But while accelerating or climbing steeper hills, a much higher RPM is sometimes appropriate. I routinely hold 4500+ for a minute or two on the freeway when climbing steep hills, shifting to 2500 or so coming down those hills, and then running 2700-3000 RPM on flat-ish highway. If you need to accelerate quickly, floor the throttle and don’t shift until redline. Better to rev it than lug it.
