The Thermaltake V9 cases are 8.19 inches wide. The 160mm tall, tower style, cpu heatsinks require a case that is at least 8 inches wide. Luckily the Tuniq Tower 120 Extreme is a bit shorter at 152mm so it will fit. As you said it will be tight but it will fit. There is sufficient space between the motherboard and the motherboard tray for the backplate.