Just a few quick questions

I have a '02 V-6 Mustang that is stock for the most part (i have replaced the air filter with a K&N high flow air filter). I ]have had it for about 2 and a half years. this is my first car as well as the first car that i am trying to work on. I Love My Car

Ok, with that said here are my questions:

1 - i am replacing the stock exhaust manifold with MAC headers. are there any known problems that i need to be concerned about with this? and because i eventually want to put on a true duel exhaust kit with maybe an X pipe is this the right header for the job?

2 - i am going to put on a cold air induction kit on after i replace the headers, i have read that there is a problem with the check engin light keeps comming on after that. is that a normal problem? does it happen to all cold air kits for the V-6 or are there only certain kits that i need to stay away from?

3 - if i do replace my air induction system do i also need to replace my throttle body.

and lastly... for now
4 - if i wanted to change my rear dif. is it really worth the hassle do you get any real performance differences?

well thank you all for reading this post.
J.Flame---OUT

Well thank-you for your help.

3 weeks after header install

Just Finished the install of my headers, the first week of driving was great once the paint burned dry (i painted them glossy black i can't say that was a very good idea...they look good but smoked and smelled really bad the first few drives.)

Anyway i have been driving it for about 3 weeks now just getting a feel for it and now there seems to be a slight decrease in low-end hp, i think... well its either that or i am just getting used to the increase and unconsciously driving differently.

what do you guys think?

oh and i will attach pics in my next post.