In short I want to:

Build up a little microcontroller powered 'computer' that I can feed all kinds of data such as speed, temperature ... and do fun things such as data log, turn on LED's, display stuff on my MAX7219, run a stock speedometer, or whatever.


So I did some searching about speedometers and VSS and signals and such:
I have a Tremec TKO 5 speed which I ordered with the cable driven speedo adapter. You can see what I have here:

Forte's Speedo Adapters

Mine looks like the short one on the right with the red gear. Now I want to get an electronic signal out of the transmission, so I need to ask for an adapter. What should I be asking for? I read some things about a 2000 pulse/mile, or a 4000 pulse/mile. I am assuming that these refer to what the computer or speedometer expects from the transmission, and the actual pulse output depends on both the device itself and the gears that are used for the drive. I'm really only interested in getting as many pulses to my microcontroller as possible, and as long as I know how many pulses per drive shaft revolution, the computer can do the math for me. Also, I read that some output an AC signal, and others output a DC signal, or maybe someone meant sine wave vs square wave.

I would also like to be able to 'signal' an electronic speedometer to display the correct speed. What speedometer should I be looking for? Are there different kinds of electronic speedometers? Can I just feed the speedometer the correct electronic signal, and the odometer will work too?

Also, do the Forte adapters look like the GM piece? Maybe I can just buy one at advanced auto, and get it quicker.