^^ he is right ^^ you shouldnt have to change heads if you dont want to, unbolt all the s/c stuff & buy yourself a nice turbo manifold along with a turbo of your choice... you will also need to buy oil/water lines for the turbo & route them accordingly. also you will have to get a downpipe fabbed up.. intercooler pipes are going to have to be re routed... i can keep going but, im not gunna do all the homework for you, again like Chucez said your not the first person to do this, there is alot of information available for you to read, IF YOU MAKE THE TIME.. Also when you post a question, please go into detail... "WHAT DO YOU WANT TO DO WITH THE CAR" you will see that quote all over the place!! Why turbo over the s/c ? This can be helpful to us, in helping you pick out a setup specific to your needs & wants.. one of the best things i did was pick up a book called Maximum Boost by Corky bell... That book will teach you whatever you need to know about turbocharging & is a great investment for any turbo project..
Hope this helps
~Danno