Dum Question: What is FAST XFI?

Simply put, it's an aftermarket stand alone engine managment computer. I.E. you remove the stock ECM from your car, and install this ECM. It allows the user to manually imput what ever tune-up they desire. No need to change a compter chip. Just plug your lap top into it and start pushing buttons. NOT needed for 90% of the Turbo Buick owners, though. IF you are building a car to exceed 10.30's, then it will be a good investment. If you just have a street driven Buick, there are alot better places to spend your money. (like buying MY twin turbo car, first, THEN buy a FAST XFI to install on it.:)
its one of the top 5 best computer set ups you can possibly buy for a GN

it works by adding a wide band O2 senor, allowing for the rich or lean readings in fuel
it works by allowing you to manipulate fuel, spark, air to produce power via computer
it just works! wide band tuing is the only way to travel with a EFI forced induction car.
Correct me if I'm wrong but with a FAST XFI can't you also switch over to a typical rotary style ignition set up and use the XFI to control injection timing?