Originally Posted by
Disco Muppet
The Donaldson snorkel head (from what I've read, been looking into pre-cleaners) is generally preferable as it spins the dirt out so no need to change filters every day or so.
Another option is the SkyClone which Nugget and Chook use, and they're certainly easier to get answer out of than Donaldson. I E-mailed the bloke Nugget used and within a day he'd sent me back a form to fill out regarding the details of the engine I'd be running it conjunction with (no. cylinders, capacity, turbo/NA, etc) so they could pick a compatible filter head, which is not only as effective as the Donaldson if not more so, but it's also fully compatible on road.
I can PM you the contact info if you want :)