It depends on the import. Obviously making a honda fast has its limits as compared to modifying a SR20 powered nissan, a turbo supra or a porsche 930.
A few mods can work a lot of wonders for those kinds of 'imports' that would allow any of them to stomp on a bunch of warmed over domestic hardware.
That being said its not as cheap as warming over a domestic, but then again there are the quality and uniqueness factors to go along with it.
If you had to have an eleven or twelve second car, which would you prefer, driving a camaro or mustang or a 911 or supra turbo?