I got the finishing touches done. I added a "pre-filter" and also painted the end.
I was somewhat concerned with getting insects and debris up into the filter. After running for two weeks (600 miles) with the ram intake, I was happy to see that when I opened the airbox back up, the main air filter visually seems identical to what it was originally. Nevertheless, I came up with a good idea to make sure I keep stuff out of the main air filter. At first I was going to use a piece of window screen, but then I was an old washable plastic mesh furnace filter that I had lying around. I cut out a piece, like this:
Then I cut out a donut of plywood, and used it to sandwich the furnace filter piece against the toilet flange:
Here's what it looks like inside the airbox. I took the main air filter out just for this picture so that you can see it.
I also got some Krylon Fusion black spray paint that can be used on plastic. I used that to spray paint the end of the pipe so it's less visible. Here's the finished, near-invisible look:
As far as the FE numbers, I think there is an advantage. My average of the last ~600 miles with the ram CAI installed, I've averaged 50.28 mpg on the overhead. This is a 4.1% improvement over 48.29 mpg for the previous 600 miles. Both periods had similar tempeatures (79 deg F avg temp). I don't think it's fair, however, to ascribe the whole 4.1% improvement to the intake. Recently, I've really racheted up the hypermiling intensity in an effort to break the single tank range record. If I had to guess, I'd say probably 1% FE improvement from the intake, but it's hard to say much of anything definitative about such small differences.