Well, I wasn't sure...that's why I thought I would ask. 
You should ask some of the gas guys about the H41. It won't help you on the road much with those tires. Offroad the low first will be nice but I don't think you are going to need it on this trip.
As for the snorkel, I really like mine, but again I think you will get along just fine without it. You will also have to waterproof all your ignition stuff on those gassers, plus run your vent lines up to the top of your engine bay. You will have to do this anyway.
I think, If I was you, I would look at steeper gears or if you really want something nice, invest in a 5spd.

You should ask some of the gas guys about the H41. It won't help you on the road much with those tires. Offroad the low first will be nice but I don't think you are going to need it on this trip.
As for the snorkel, I really like mine, but again I think you will get along just fine without it. You will also have to waterproof all your ignition stuff on those gassers, plus run your vent lines up to the top of your engine bay. You will have to do this anyway.
I think, If I was you, I would look at steeper gears or if you really want something nice, invest in a 5spd.