Combine 1 bottle of beer in a large plastic container with salt, caster sugar and chilli sauce. Stir until salt and sugar dissolve. Add chicken pieces, 3 cups water and remaining beer. Cover and refrigerate overnight or for up to 48 hours.
Meanwhile, combine sauce ingredients in a saucepan and bring to the boil over medium heat. Simmer, uncovered, for 10 minutes or until slightly thickened. Store in an airtight container in the refrigerator for up to 5 days.
Drain brine mixture from chicken. Pat dry with paper towel. Heat an oiled barbecue or frying pan over medium heat. Cook chicken, covered, turning occasionally, for 20 minutes or until almost cooked through.
Set aside half the barbecue sauce for serving. Continue cooking chicken, uncovered, basting occasionally with half the sauce for 10 minutes or until chicken is cooked through. Stand, covered, for 10 minutes before serving with reserved sauce and lime wedges.