Welcome to Supramania! Your *STB* Supra is very clean. :)
I'm confused by this quote. The 1JZ didn't come with 300+hp. It was in the whereabouts of 270-280bhp. The 2JZ, however, had 320bhp.
If that wasn't what you meant, I apologize.
If you were saying that you wanted to get a JZ motor...