We get asked this question a lot so have a look at this thread which covers the basics.
I have to admire your ambition though!
http://www.torquecars.com/forums/f101/adding-turbo-nasp-engine-15003/
Cheap turbos can be purchased from breakers yards which are ideal for a try it and see type project.:bigsmile:
There is nothing stopping you but the money and hassle will just not be worth the power gain you get. It is better to just buy a better car for your tuning project.
Adding a turbo is a major engineering task and without a kit with full instructions and all the parts you need there is a big risk of blowing up the engine. Expect to spend 50 hours upwards on a project of this type. This is not the sort of modification unless you are mechanically competent.
It is worth looking at superchargers as these are easier to install than a turbo is.
Have you looked at the eaiser and more rewarding (in terms of power gains) option of fitting an Evo engine?