lots of good options, the best value is probably the MAD one. no leak, spot-on fitment, and lifetime warranty.
https://store-gd6olw6.mybigcommerce.com/mad-bmw-toyota-supra-b58-charge-pipe-f-g-chassis/
It ranges from 3 to 6 percent depending on the fuel used
Stage 1 91 octane: up to 22% HP / 25% TQ
Stage 1 93 octane: up to 25% HP / 25% TQ
Stage 1 E30 octane: up to 28% HP / 27% TQ
Stage 2 91 octane: up to 26% HP / 28% TQ
Stage 2 93 octane: up to 28% HP / 28% TQ
Stage 2 E30 gas octane: up to...
Waiting on Active to receive their shipment, no one's going to have it in stock until the shipment is delivered to the manufacturer. Its getting closer