The issue with the 1UZ has always been lack of performance parts. They're great if you're a fabricator or can afford to have that stuff custom done...
In the Supra world it's kinda laughed at because it's a whole lot of hassle for only 1.0 liter difference. Same amount of work, better aftermarket support, and more engine bay room with an LS motor
Waiting for someone to toss a 3UR in one of these cars... but again, expensive...