Before a huge argument begins about what the best intake is, let me help ya out by saying that no intake will automatically void your warranty. For a warranty to be voided, an issue has to occur that your dealer can prove was directly caused by the intake. Be safe and call your dealer too, and ask them how they handle all that.
Most people on this forum will tell you to use the fswerks cool-flo intake, and rightfully so it's an awesome intake. It's a true cold air intake so if you live in an area where it rains alot and lots of deep puddles form, you may want to consider another intake as you could hydro-lock your engine. You have to pretty much completely submerge your intake to hydro-lock it, but it's still an issue to consider (and if you're worried about warranty issues that would definitely be a big one).
The steeda intake is a good intake too, and with that you avoid any chance of hydro-lock because even though it's called "cold-air" it's really a short ram intake. But if you have long commutes in hot weather, you'll most likely have heat soak issues. It mostly comes down to personal preference, so it's pretty much up to you. Hope this helps!
comming from a guy who runs the fs works....this intake has performed flawless for me and yes i'm from south florida where it rains a hell of alot.....I'm just cautious it's not that hard to do.....I was worried about it at 1st but for like the past 5 months it's been awsome and you can hear it too! which is a plus
No you won't void your warrenty we as car buyers are protected by some act I forget the name if someone remember feel free to say it. You can only void your warrenty like this, ama give you examples much easier to understand,
If you are using a cold air intake and you hydro-lock your engine then yes thy can void doing anything to your car
But if you are using the cold air intake and your transmissing starts giving out and they can't prove other-wise then you are still covered.
So pretty much you can have aftermarket products on your car and not void anything unless that aftermarket wasfault of cause.
As far as best intake for our fofo's probably fswerks best priced, they engineer for OUR cars and the fiestas now, unless you go diving in water , or passover rivers with full throttle its close to impossible to get a hydrolock, I'M NOT SAYING IT IS IMPOSSIBLE, they also came with a sleeve you can put around the filter that reflects water that will help greatly. I would never go with short ram. Ever.
I vote for FSWerks, been running it for over 20K miles with no problems. Now, to be fair I do live in the Desert SW / Las Vegas, and it only rains about 4" a year, but when it does rain we get flash floods that results in a lot of water crossings.
Any of the aftermarket intake systems will work as they were all designed to work on our cars. It really comes down to money and personal choice.