The Supra is currently being destroyed by the M2 manual. Both are different buyers than a Z4. That being said, the take rate on the E85 3.0 manual in the North American market was about 40%. I think you'd see a marginal increase in volumes overall but not by much with approx. the same split as the E85 if I had to guess.
In the US, Supra volumes were down 27.5% in 2022 to just under 5k and are on track for a 50% reduction in 2023.
Sources:
https://carfigures.com/us-market-brand/toyota/supra
https://www.goodcarbadcar.net/toyota...sales-figures/