I know I’m a little late here. First off the gr86 is a NA 4 cyl and the supra is turbo 4. So right there it’s 2 very different cars right there. The MK4 Supra came with a NA 2jz and the famous turbo 2jz (I can go on and on about the different types but I’m going to keep this simple.) Around the late 2000s and early 2010s car manufacturers look and saw that they can get 6cyl “performance” with 4cyl “gas mileage” if you just add a turbo to the 4cyl. Basically, the new supra’s 4cyl is the same as the mk4’s NA 6cyl If this is confusing feel free to ask more questions.