Trim the silverskin off the tenderloin — it won't break down and will toughen the meat. Pat dry with paper towels. Season all over with kosher salt, black pepper, and garlic powder. To marinate, combine soy sauce, honey, garlic, and mustard (or honey-Dijon-chili powder) in a sealed bag; marinate at least 1 hour, up to overnight in the fridge. Pull pork out 15 minutes before grilling and shake off excess marinade. Discard used marinade unless you boil it thoroughly first. Oil the grill grates lightly just before cooking.

将烤架预热到中等热，并进行两区设置：一侧直接热，另一侧间接。加热至少5分钟，然后清洁并油栅栏。 在直接热上煎烤里脊肉，每隔几分钟转动，直到在所有边上焦化——总共约10至15分钟。 移动到间接热，关闭盖子，并烹饪直到即时读取温度计在最厚部分读63°C。总烤架时间通常是16至24分钟，可能长达30分钟，取决于烤架温度和大小。不要仅依靠颜色——使用温度计。 如果用烧烤酱涂抹，在间接热阶段应用并转动一两次以建立轻釉。

Pull the tenderloin at 63°C internal temp. Transfer to a cutting board, tent loosely with foil, and rest at least 10 minutes — this keeps the juices in the meat. Slice against the grain into ½-inch medallions. Interior should look slightly rosy. Don't go past 68°C or it dries out fast. Always use a thermometer — don't rely on time alone. Serve with boiled reserved marinade and your chosen sides.