Im assuming that your not in the US seeing that you have a R33 Skyline (unless you imported it?), so I dont know how much of this would apply to you but hope this gets you started. First are you going to be heavily modifying for performance at all? If so then the answer is easy. Get a standalone ECU like the AEM EMS and you will have no choice but to have a PC hooked up to it whether via laptop or PC.
If not, then heres some informative sites...