Quite commonly when it comes to increasing power there is no cheep answer to making a car fast, and the biggest setback for making some cars fast is do they have the parts market to support adding power?
Can the transmission and support added power? and if not which is quite commonly the case, what do they have available as far as making your transmission a little more rugged?
Can the cooling system keep the engine cool when under boost? and if not what do the have available for better radiators and cooling systems that can keep the engine cool under added power?
Will the fuel system continue to add enough fuel for the increased air flow because of the turbo? if not are there parts available to meet fuel demands for boost?
and is there ways to tune or program your cars PCM to run boost?
How about the engine itself? can the crank, main and rod bearings handle the stress? how about the head gasket, can it take increased combustion chamber pressures?