The Type A4 gets more simple. A more minimal upper and thinner sole help reduce weight and thus increase speed. Ideal for 5k and 10K road races and if you are an elite runner, it will work for the half marathon. The flatter midsole (4mm difference from heel to toe) also makes this shoe a great option for minimalist runners.
The Grid Type A4 is a moderate feature, minimum neutral shoe designed for racing. It is built with a curved shape.