If i were to turbo an A14 first thing i would do would be to buy an efi kit for it.

You'd then have to make up an intake plenum and intake runners.......the plenum has to be a specific volume relative to the capacity of the engine, i forget what it is but someone will be able to tell you.

On the exhaust side you may be able to modifiy the original manifold so a turbo can bolt onto it. If you were trying to do this cheap get a turbo from a jap import place. not sure what car you'd get it off Maybe a starlet GT possibly a CA18, don't want too bigger turbo.

If your A14 is pretty stock it won't be able to take much boost. You may also need to lower your compression a bit. You can get copper head gaskets made. I've seen other people use two standard gaskets to get similar results.

well thats just to give you an idea. Theres prob heeps of other stuff like turbo pluming and tuning etc.