I go by engine feel and sound. Drive your car hard for long enough, and you will get the other senses picking up the right shift points.

 

Yeah.. now that I have a complete set of Fabspeed installed, I think it is much easier to shift at the right time compare to stock.
Gonna have my 1st Driver Skill on a Porsche mid April, so I am sure things will only get better =D

 

I have one on my race car. It's integrated into the AIM data system. Programmable lights - looks similar to the one on the link. Each light goes on at a certain RPM so I have it go off like a Christmas tree when it's time to shift. Pretty useful on the track. I don't need one for the street car as I seldom wind it up that high, and when I do, I'm paying attn...

 

For the minimal cost of incorporating a shift light or audible warning, it would be nice if they were included. My 74 Mazda RX4 (I know, I'm old) had a great loud alarm that sounded as you hit the red line. I would find it a big help when autocrossing, as I'm so busy watching for the next gate etc. that it is easy to hit the rev limiter. I'd prefer a warning just ahead of that. I'd prefer that over the useless sport chrono dial.

 

We've installed that Ecliptech Shift-I on a number of projects and for those who desire a shift light it's a nice solution, can mount in a variety of spots and fully programmable.

A few quick pics on a recent build: