||OK, I agree the Outerwears Pre-Filters are pricey, but I really think they're worth it.
I've been running a pre-filter on my RC8 for about three gallons, and I think I can say that:
- it extends the time between filter service/cleaning in dry conditions;
- it protects the filter foam to get soaked if you hit a puddle in a wet track (believe me: here in Rio de Janeiro it's rainning a LOT lately);
- it is easy to clean: just wash it down with dishwashing liquid, let it dry, and use again!