Okay, it's not really a mod; it's just new floor mats. But they're not just any floor mats. I can't see paying $80 for the OEM floor mats, especially when all I really need is the driver's side, but they don't sell them individually. I've shopped for floor mats at Wal-Mart and Autozone, but didn't find any I liked. It's hard to find ones that fit right and don't slide around. I thought about diamond-plate floormats, but I'm not sure if I'd like them, and don't really want to spend $100 or more for them. Part of the problem with most floormats, is that the nubs on the back are too small to really grip the carpet. However, chairmats have longer, sharper spikes that do a pretty good job gripping the carpet.
The smallest, cheapest chairmat ($15) is just the right size for the front two floor mats.