Aftermarket EFI systems?

[Jesse R. Ortiz]

Has anyone here ever had any experience with a TEC II, Haltech, Simple
Digital Systems, Accel, or any other Aftermarket programmable engine
management systems?  I'm wanting to get more info on the difficulty of
programming, and the results that they give, such how 'streetable' they
really are. Could they be used on a daily driven car without "headaches"
once they are programmed? How difficult was it to attach to the wiring on
the car such, such as for fuel pump, ignition switch, etc?
Thanks..
Jesse.