Factory vs aftermarket (part1)

[LotusM50 at aol.com]

In a message dated 97-01-25 04:08:22 EST, Tomchou at aol.com writes:

<< Look at the aftermarket companies that are tightly connected to the Big 3,
 such as McLaren, Roush, Shelby to name a few.  If you talk to their people,
 and look at what they do, you'll see they use very few of the usual popular
 aftermarket products out there.  Most of their creations use very factory
 parts or custom ones they design for that specific application with
 complementary changes in software/calibration or other components to
 compensate any side effect.  No "black magic" gimmicks such as air foils are
 used.  Look at the totally factory backed high tech race teams in endurance
 racing, off road series, Indy Car/CART, Indy Lights - you don't see the same
 stuff being used as the popular auto mags such as Hot Rod, Car Craft and
such
 advertise/evaluate. >>

What do thry use to control and program ignition and fuel.  And can mere
mortals like me get access to them and perhaps buy them?