I have a 1995 buick Lesabre and i want to change from a series 1 non supercharged to a series 2 supercharged i wanted to know what i need and how much work it will be

You MUST have:

Supercharged Engine (complete)
Transmission from the donor car
Axles from the donor car
PCM from the same car
Engine wiring harness from the same car
Factory service manuals for your car and the donor car

You SHOULD have:

Alot of patience
Experience in doing this kind of work before
Willingness to do custom wiring
Suspension components from an SSEi
Subframe from the donor car

Check out http://forums.motorswap.org/ (formerly L67swap) for similar swaps.

do u have to have all that can i just replace motor and wiring harness

You have to do all that.

You could with a chip but your trans will die very quickly.
Its better to get the trans the engine was designed for. And while your at it, the pcm designed for the engine/trans combo.