Mustang Gt or a GST i am sorry i read that u just compared these two cars i think i am gonna cry now what do u want a older 5.0 or a 4.6 do u want a new body style or a SN95 or a fox body. I would go with a supercharger over a turbo on mustangs their are just not as many that have turbo's and if u have problems that is less places to turn to also the turbo kits seem to cost alot more. I can tell that with boost eighter way if it is tuned right u can get some fairly good gas milage out of them. cons is heat if u have compressed air u will get more heat but this is not a big issue and can be fixed with a inter/aftercooler or if dont run to much boost. Also superchargers dont get as hot as turbos eighter. Some people dont like the wine u get from most superchargers but there are quite ones u can buy as well. If u have any questions this is a good site just ask.