After a long and successful run, Saturn decided to replace the S-Series with the Ion in 2003. The new model gave loyal Saturn consumers a roomier, sportier, and more powerful version of what they had come to expect over the years. As in previous Saturns, the 2003 Saturn Ion used polymer based panels to minimize scratches and dents. In addition, the car operates with a 2.2 L, 140 hp engine, an improvement from the 1.9 L and 124 hp in the most powerful S-Series trims.

The 2003 Saturn Ion comes in 5 different trims: Sedan 1, Sedan 2, Sedan 3, Coupe 2, and Coupe 3. All trims have standard 5 speed manual transmission with optional ABS brakes and traction control. The sedans have optional 5 speed automatic while the coupes offer optional continuously variable transmission (CVT; see earlier Saturn VUE models). In addition, all trims give you 25 mpg in the city and 33 mpg on the highway. The coupes seat 4 and the sedans seat 5. Other innovations include 4 doors on the coupes and trunk space in the sedans that has increased almost 2.5 cubic feet from the S-Series.

Overall, consumers agree that the 2003 Saturn Ion represents an upgrade from the S-Series. However, many wonder whether Saturn did too little too late. Occasionally rough handling, road noise, and internal vibrations detract from the driving experience while hurting Saturn's initial position against competitors such as the Civic and the Corolla. Like Chicago Cubs fans, Saturn consumers would have to wait til next year for the home team to come through in the clutch.