Lots of examples of 2500's vs 3500's where the only difference was the springs...or even just the overloads. And the weight sticker of course.
However, there are ZERO examples of 1500's vs 2500's that can say the same.
Aside from being visually similar to a degree, you can agree that the difference between a 1500 and 2500/3500 is more than just springs, right?
2500's really only exist for classification purposes. People that need more than a 1500, but don't want to pay for the full Class 3 license and insurance, which is significantly more than Class 2.