Since NO vehicles come with them, the deduction would be zero benefit. Why would it need to be filtered?
Aside from the overflow tank, it it a closed system so nothing would get in.
The only contamination would be from corrosion and that would be from weak antifreeze.
The passages are not that small.
2003 TJ, 33" BFG AT, 2" BL, 2" BDS spring lift, Truck Lite headlights, Homemade sunrider top.