* Positioning and Price: The GTX was positioned as Plymouth's top-of-the-line performance car, a step above the Road Runner. This meant it was generally more expensive and came with more standard features.
* Intended Image: The Road Runner was marketed as a more "fun," less luxurious, and arguably more rebellious muscle car. Its marketing leaned heavily on the Looney Tunes cartoon character and emphasized raw power at a more affordable price. The GTX had a more sophisticated and refined image.
* Features and Options: While both offered powerful engines, the GTX typically came with more standard luxury features than the Road Runner. Things like power steering, power brakes, nicer interior trim, and more advanced suspension options were more common on the GTX. The Road Runner often had a more spartan interior focused on performance.
* Performance: While engine options overlapped somewhat, the GTX sometimes offered higher-performance engine options or more readily available higher-performance options. However, the difference wasn't always significant, and skilled tuners could make either model extremely powerful.
* Body Style: Both were initially offered as two-door hardtops and later as convertibles, but the subtle styling cues differed; the GTX generally sported a more aggressive and luxurious appearance.
In short, the Road Runner was a more affordable, stripped-down muscle car focused on raw power and a fun, quirky image. The GTX was a more luxurious and refined performance car aiming for a higher-end buyer seeking more comfort and sophisticated features alongside strong performance. Think of it as a "budget" muscle car versus a more premium muscle car, even if both were capable of serious performance.
