Like the others have said, an intake won't really do too much for MPG's.
There are several options that were posted up... the DIY
with the 6637 filter (or the Tymar which is a similar setup, but sold as a complete kit rather than piecing it all together), or an intake setup like the AFE or S&B, or going with the Ford AIS (an upgrade heavy duty intake and filter that fits like it was factory installed). Any one of these are good, and the biggest differences are going to be maintenance, noise, and cost. Many of these setups can help a bit with EGT's too.
The Tymar and the DIY
are the cheapest. They do filter very well, and many people like the looks of a huge filter in the engine bay. The drawback is that these are the noisiest setups. So if you like hearing turbo and engine noise, it's great. If you don't, you might not like it as much.
The Ford AIS is a severe duty filter. It's expensive, and the filters are more pricey than stock replacements. However, these filters do last a long time, and trap a ton of dirt. These are also very quiet setups, and will keep noise levels same as stock.
The others like AFE, S&B, etc. do a good job at filtering, and most come with a shield around the filter. These aren't quite as noisy as something like the Tymar or DIY
, but they aren't as quiet as stock either. Some of these setups are pricey, but most come with reusable filters, so the lifetime cost of the setup is somewhat lower than those that require new replacement filters.
That's the short and skinny of it. Take your pick.
Me personally, I've run the stock setup, the DIY
, and now currently run an AFE Stage II with the Proguard7 filter. I personally prefer the AFE simply because I don't have to buy new filters, and it's slightly quieter than the DIY
. Other than that, there's really no difference between the DIY
and the AFE in terms of performance.