SIN Car Accessories and Customization Options

I've been a fan of SIN cars for years and I'm excited to see the variety of accessories and customization options available. The carbon fiber trim kits and performance exhaust systems are definitely eye-catching, but I'm curious to know more about the interior upgrade options such as custom seats and infotainment systems. Has anyone tried out the premium sound system or the navigation upgrade? Would love to hear about any personal experiences or recommendations for taking my SIN car to the next level.