I want to modify the ECU to either A get better fuel economy or B
limit the max speed that can be achieved. What is the exact process
for an OBD II type car? What equipment is needed(apart from a laptop &
OBD interface)? Is it possible to change these settings dynamically ie
while in motion?

I typed in "modify ECU" "OBD II" to Google and came up with a bunch of
stuff. The first site I looked at seemed to have the information you
need; if not, they encourage you to call or email.
http://www.andywhittaker.com/ecu/obdii_hardware.htm and their software
link which has FAQ's at
http://www.ross-tech.com/vag-com/vag-com-faq.html

thank you far that - however i am capable of doing google searches
myself and have been researching this for some time now

i am pretty sure(99%) these things are possible

i want an exact description of how to go about it and what i need to do it
and i want to pay for it and not waste someones time teaching me stuff for free

thks and good luck