I love my Flowmaster cat-back system, until the muffler got a loose baffle inside this summer, now it has a rattle at certain rpms. Time to get another one
I was going to get a K&N CAI eventually, but when AEM came out with their oil free filter I want one of their kits instead.
http://www.performance-air-filters.c...&b randid=486
What engine again? I know that none of the programmers can change the speedo settings for the v10 SD, I'm not sure about the other engines but I can find out for you. The speedo can be adjusted by a service department up to a 35" tire accurately.
I suggest searching through this forum, lots of Ford tuning experts here -
http://www.ford-trucks.com/forums/forumdisplay.php?f=46
From reading the forums there over the years it looks like Superchips or Diablo are much better than the Hypertech programmers, at least for Fords.
I think you would see a performance difference, but it won't be a huge change. What gearing you running?