Right now I'm leaning towards, just replacing the stock air filter with the K&N, and the oil filter too, with either K&N or Royal Purple.
The BOV I'm mostly neutral on. Pro's include, the price, ease of install, and no evidence (as yet) it will do any HARM.
I've been on a lot of boards, (full disclosure, to include counting some amazon-reviewer-yuks) and/but this is the first I've heard about K&N stuff actually doing damage.
Coming from the guys that have DONE K&N the praise is pretty consistently unanimous. But now I will actually try and seek out criticism ref K&N.
Personal experience; when I put the Steeda Short Ram on my 07 Focus there was a small but noticeable, (maybe like 3 - 6%) uptick in mpg and/or 'ass', depending on hard I pushed it, (you got one or the other) But, admittedly, that Duratec was a totally different animal from the current EB.
Also I only re-oiled the filter after very first time I washed it. After that I just said screwit, washed dried and slapped it back on. 10 years and almost 70k miles later the engine has never shown any signs of having a problem with that. NOW THAT SAID a recent "deep-clean" fuel-system clean, with the more expensive crap you're supposed to run through on as close to an empty tank as possible, while it didn't blow visible smoke, the after-effect performance change was VERY noticeable. Perhaps that's the K&N take-away. If you're going to use something that might be guilty of letting a little more dirt get through, compensate by being a little more religious with the fuel-system cleaner additives....?
Lastly 1.5 v 2.0. At 60+ now I'm significantly more interested MPG over performance. (1), and 2.) Looking as FORD's Fusion Engine-spec sheet with all the possible engines & tranny's, It sure looks to me like the 1.5 best hits the sweet-spot balancing MPG with HP. (seen in this side-by-side chart)
(You would not believe how hard this chart is to find). (Thank You Ford CANADA)
AND LAST but not least. I'm cheep. To get the 2.0 is a SIGNIFICANT price bump (like about $3k) over the 1.5, I'd rather put the money into leather and the 11 speaker Premium Audio
Getting back to the MODS I also DO plan on, before making ANY mods, running out (at least) several tank-fulls and getting specific numbers on MPG, and some "feel" for the as-is performance. So I'll have some basis of comparison, whether I do just the filter elements or full CAI.
Thanks to all