I now have a Raptor shift light and its working great. However, it's settings dont agree with my factory tach. There is a 300 rpm difference roughly. To shift where my tach says 5900, I have to set the Raptor to 5600.
That sounds about right. I did a calibration check on a spare 89 Mustang factory tach I had and the high RPM range was about 300 RPM off. The tach can be made to read dead on for a very narrow range of RPM, but it will probably be off by 300 RPM somewhere else in the range.
The 92-93 tachs supposedly have a better calibration setup, but I have an older tach and can't verify that statement.
Yes.
Besides its safer lol. Keeps you from over revving. If you take it to the track you can always see where the car likes to be shifted and adjust accordingly