first of all when you say you want alot out of your viggen exacly what do you mean...how far do you want to take it.
your options are endless depending on how much you are willing to spend. do you have your viggen chipped now, and still want more out of it?
im pretty sure you can see upwards of 300 hp on the stock viggen turbo....
if you are looking for over 300 you will haev to rework alot....you are looking at new turbo, upgrade internals, fuel will have to be upgraded (regulator, injectors, and prob fuel pump..) also if you are going bigger turbo you will have more turbo lag than u have stock, but the tradeoff will be in the upper rpm range....
there are advantages and disadvantages of going both ways. if you have only 1500 to spend, and thats all your looking to sink in i would go about it another rout,...im not sure what u have done now but id take that money and invest in,,
diverter valve $130
have throttle body honed.--?
that is just my opinion..hope it helped...now if you have alot more moneyto work with and you wanna make this viggen REAL sick..then your oportunities are endless. more hp more money..the game is not cheap
im not sure what the viggen turbos can handle horsepower wise, but i heard that the stock blocks can handle up to 300 hp....now thats moving..
if you do decide to get another turbo, let me know, ill take that ol viggen turbo of your hands...