Long tube headers will make your exhaust a little louder. I always run chatted systems and they will cause a check engine light. There are tuners out there that can tune for headers to pass emissions as long as your state is only doing an OBD2 check. If you have a visual or sniffer test you will...
You need to decide if you want appearance. Performance or a combo of them. I personally choose performance first then looks. The only way to know if the dealer will fix your issues is to take it in. I would think that those problems are covered under the 3 year 36k warranty.
Here's what I did...
Unless you know how the tuner set it up I wouldn't run it. Some tuners just turn off the rear O2 sensors and others make changes so that they still work.
I didn't recommend that he use 10w-30 I just said it will not damage his engin based off of my experiences with my 2011. When I tore it down to put in forged internals my block just needed a slight hone and showed no signs of excessive wear.
I ran 10w-30 due to lack of availability of 5W-30 where I was living at the time not for any other reason. I still stand by my my statement and experiences that its not going to cause harm to the engine.
While I do not disagree with what you are saying about viscosity and engine wear at start up 10w-30 will not damage these engines. I ran 10w-30 synthetic for years in my 2011 supercharged GT and never had any issues.
If they do the track key like they did on the Boss 302 it will work like this. Purchas the kit and ford will re flash your computer and provide you with two keys. These keys will have a chip in them that will interface with the cars computer and it will know if it's the street or track key.
I...
I've used a variety of headers over the years and I really liked the fitment of Kooks headers. Any tuner can shut off the rear O2 sensors to eliminate the cell.
Borla makes a kit part number 200127 it's $10,475 you can check it out here http://www.borlainduction.com/200127-v8-kit-ford-coyote-50-barrel-throttles-35mm-air-horn.html