if you visit the pennock's fiero forum, there has been alot done to the 4.9L caddy engines for performance, including turbo charging...there is alot of info on the type of engien mods you are doing to the 4.9L.. unfortunately, because the 4.9L cadd engines dont use a knock sensor, youll have to use an entirley different computer if you plan to use more than 6 psi boost... visit
www.fiero.nl
post on the group about what you wnat to do.. there several hotrodding build up threads for the 4.9L engines and also some about turboing it as well.. take care