Preheat grill to medium. To make confit, place garlic in a saucepot and cover with 1/3 cup olive oil. Bring to a boil and then reduce to a simmer. Cook on low heat and for 25 minutes.
Snap the asparagus to remove the stems. Lightly coat the asparagus spears with 2 tablespoons olive oil. Place on grill and turn frequently to char lightly all over, about 3-4 minutes. Let cool, cut tips off, and slice remaining stems the same size and place them all in a medium-size mixing bowl. Halve or slice the olives to match in size. Dice the roasted peppers and red onion, then add the garlic confit, basil, and balsamic vinegar and combine.