Well, I totally get the anxiety about the Stow 'n Go tracks getting filled with Cheerios and mud. Honestly, when we first got our van, I spent way too much time researching the technical specs of the floor layout because I was worried about the sliding mechanism. I'm still a bit of a beginner when it comes to aftermarket mods, but I've learned that the Pacifica’s floor is actually a bit of a technical nightmare for mat manufacturers because of those deep sliding tracks.

Here's what I recommend based on the data and fitments I've looked into:

• WeatherTech FloorLiner for Chrysler Pacifica is the industry standard for a reason. They use digital laser-mapping to ensure the fit is precise. Tbh, the material is quite rigid (High-Density Tri-Extruded material), which is great for holding its shape against the tracks, but it can feel a bit "plastic-y" under your feet.
• Husky Liners WeatherBeater Floor Mats for Chrysler Pacifica are a solid alternative. Ngl, I actually prefer their "Stay-Put Cleats" on the bottom. Technically, they use a more flexible rubberized material that doesn't bunch up as much when the cabin temperature fluctuates. It's a very decent option for kids.
• Smartliner Custom Fit Floor Mats for Chrysler Pacifica (3 Row Set) is a great budget-friendly option that covers all three rows. The technical fit is surprisingly tight, and it covers the center aisle well.

The big lesson I learned is that no matter how "perfect" the fit is, you’re almost always gonna have to pull the mats out if you want to actually stow the seats. Most of these high-wall liners are designed as a single piece for the rear rows to prevent liquids from reaching the carpet. It’s a trade-off between protection and convenience, I guess! Hope this helps!

Commenting to find later