But those are JDM cars. You probably will not be able to register those cars here easily; moreover, they are right hand drive, something I do not prefer here in States. I agree with you though, performance wise, GTR is a more desirable car.
As far as paying 15-20 goes, it's completely personal. I've always had a thing for Z32s. You can easily find TTs under 10, but those won't be clean.