Pros

• Drivers with high-power vehicles love the RT660 for its high-grip off the line and short warm-up time keeping their tires sticky. Utilizing its soft 200 UTQG compound and massive contact patch, the RT660 is impressively grippy with little warm-up, especially in terms of longitudinal grip for those extra-torquey engines. 
• One of the only soft-compound Extreme Performance Summers with a directional tread pattern, allowing for tire flipping to maximize tire life, whether it's due to outer edge wear on limited-camber setups, or inner wear from camber-heavy vehicles. 
• A broad range of production sizes, with many niche sizes readily available means the RT660 can work on almost any vehicle and setup. Whether you're looking for some more grip for your retro Mustang, or want something sticky for your Miata, the RT660 has you covered. 
• Top pick for autocross and time-attack drivers, great for light-track-duty. 
• Healthy for your wallet! Generally lower prices than competition.

Cons

• Not a daily driving tire due to limited durability and wet grip.
• Summer only both due to limited grip in cold and wet conditions, and potential cracking when stored in 7°C or colder temperatures.
• Prone to overheating after extended usage, leading to the tire becoming greasy and losing some grip capability, slowing lap times. 
• Wet grip leaves room for improvement, losing some time to competitors in adverse conditions.