There are turbo kits that simply will bolt on to your 420a engine, and will give you 40-75 horsepower, they'll run you from 1500 to 2000 dlls or more,
http://www.hahnracecraft.com/ here you can see some good kits, and it'll help you on what your looking for, they also have some good advice...
if you want to increase the power after the turbo kit is installed, you'll have to upgrade your fuel system, pistons, exhaust among other things... you are loking at over 3000 dlls to your engine, and still will not be as good as a factory turbocharged engine, so im my opinion, put money to your car to make it "nice looking" and sell it, then you'll find a good turbo car, and you'll be more happy, but it takes time... so it's your choice...!
