I wouldn't consider any 9 ports for GT anymore. They are simply too much top with not enough bottom and at a steep price. ROAR has this one right with the 5 port. The balance of top end with enough grunt to pull the 3500 gram GT out of the corner is perfect. Given your input on durability and quality its really a simple answer. Get over to Uriah at Murnan Modified Motors and pick yourself one of his powerplants. Many racers rely on his expertise and are putting down Murnan power all over the world. I love them and Grenade will second that. You can't go wrong.