back pressure?

[Durwood]

I'm leaking oil from my rear main seal. I lose about a quart a week (though not all from the rear main seal, ha!). I've got a chrome open style air filter on, and I recently read that those can cause high back pressure, forcing oil out the rear main seal.

Any truth to this? And I might as well ask... What's the easiest way to change the rear main seal?

Thanks!