1. BIG ACVW engines cost lots. Lots and lots. 1600s or 1679s with basic ported heads/compression/cam/carbs, and a close 3rd and 4th in a stock-ish gearbox don't.
2. A hot 1600 in my '73 Super would do low-15s, coz it weighs 900kg or so (street spec).
3. A hot 1600 in a stripped-out '63 Beetle would do high-13s, coz it weighs 660kg (race spec).
High-13s in a Beetle will suck the mirrors clean off a hot hatchback that runs high-12s, coz it will stomp off the line not spin up.
Have fun!