It Mainly depends on the engine your planning on useing.
How tired is it?
What has already been done?
If the engine is ok, then start from the block up, and get bigger everything.
Intake, Throttle body, Cold air, heads would be nice, mild cam, roller rockers 1.5/1.6/1.7 depending, headers, bigger fuel pump, and so on...
Then the electrical, you Should have gauges to watch things, advance controler, and more.
An intercooler would be a good idea to at least plan on, but not needed right away.
Basicly, a blower is a big job.
Your going from training wheels, to a jet car.
I have heard of people just slapping on the blower, but they normally end up breaking stuff after.