I promised that I would do a small write up on "How-To HKS Turbo Timer Install on S13" after figureing it out. The reason being I could'nt find any simple directions when I needed them.
I want to make this very short and easy to understand. I dont want to go through the proccess of removing panels and such.
That should be common sense and easy to do. 
I only want to focus on what wire goes to what wire. 
We all know where the ignition switch is I believe (It's where we stick and turn our keys to start our babies!). Once you have the two panels covering the switch off, you will notice there are 4 sodered wires. We will only need 3 of those wires.
These are the wires on the Turbo Timers harness, and what they are.
Green wire- Goes to 12 v ignition
Red wire-Goes to 12 v constant
Blue wire- 12 v accessories
Black wire- ground
Gray wire- e-brake
Now I will tell you which color wire you need to splice the green, red and blue wires into.
But wait!!!!! DO NOT leave your battery connected!!!
We do not need to blow any fuses. Unless you are..... you know....
TT Harness Ignition switch Wires
Green wire will go to Black wire with White stripe
Blue wire will go to Blue wire
Red wire will go to White wire with Red stripe
Gray wire will go to Yellow wire (the one and only wire connected to the e-brake)
Black wire will go to any ground (Bolt it down to a good chassi ground )
Now tuck everything in neatly and plug up your battery. Read your instructions manual so you can set up your TT and WALLAHHHH!!!!
(P.S You may choose to connect the wires cleaner than myself
. I like the dirty old school way of wire to wire, twist, and tape 
) Enjoy mis Amigos!!!