To answer both of the above questions:
1. As far as my recommendation, I'll know for sure in a couple weeks once I help DAVESNELLING install the one he just ordered. I carried my Stillen over from my coupe when I traded, but when I had my coupe, I knew the Injen was the best performer and only chose the stillen b/c of potential hydroloc issues on that low car, which won't be a concern with the FX (unless you plan on fording any 2+ft deep streams). If I were buying an intake today for my FX, the Injen would be my first choice.
2. The Injen replaces everything in front of the throttle body (with the exception of the MAF section, which it integrates), so no accordian piece to mess with and no need for the separate Z tube. It further extends down into the bumper area, placing the filter in front of the radiator (a bit of speculation here, as I haven't actually seen it, but that's how it is on the Z and G), making it a true cold air intake. I'll make sure to take pics during the istall, do a write-up and hopefully will have before and after G-tech runs (though they may not show much right away since the ECM will need time to adjust).