Besides an optional massaging lumbar driver's seat in the STS, Cadillac added nothing new to the 1999 Cadillac Seville. The SLS and STS remain as the 2 trims. This midsize sedan seats 5 and has 4 doors. In addition, the Seville uses a 4.6 L V8 engine with 4 speed automatic transmission. The main difference between the trims comes from the horses under the hood. The SLS comes in at 275 hp while the sportier and more powerful STS comes in at 300 hp. Both the SLS and STS get you 17 mpg in the city, 26 mpg on the highway. Standard features include air conditioning, power windows, power door locks, leather seats, power seats, cd player, ABS brakes, and traction control. Sunroof comes as an option. With little to no change from the previous year, the 1999 Cadillac Seville left itself open to the same questions about its durability and maintenance. Consumers consistently mention the high expense involved in upkeep despite the car's elegant appearance and quality performance. As with other Sevilles from the mid to late '90's, make sure your model has a clean bill of health before you buy.