lincoln+ford,
Not to insult your intelligence, but do you understand the difference between a stand-alone and a piggy-back system? Most "burned chips" are piggybacks, which do not replace the stock computer. Instead, these "chips" only give the user the ability to modify the programming in the stock computer. Stand-alones replace the stock computer hardware completely.
This has little to do with FMUs. The only relevance is that at some point before we had the ability to modify the tune in the computer, people would use FMUs to give the car additional fuel. FMUs are essentially boost-sensitive fuel pressure regulators (FPRs) that multiply the fuel pressure based on boost pressure. A 4:1 FMU would provide 4 extra psi of fuel pressure for each additional psi of boost (psig). Adding fuel pressure in this way circumvents the need to tune using the computer. It's a relatively crude method, but it has been used effectively in a lot of tunes. FMUs can also help to make up for injectors that are smaller than they should be. Negative side effects of FMUs include the large strain they place on fuel pumps and inadequacy in tuning the entire powerband. Imagine running 10psi of boost with a 4:1 FMU. The FMU attempts to compensate by adding 40 psi of fuel pressure! Now your fuel pressure is a stratospheric 80psi, and even a high-pressure walbro will struggle to move adequate fuel for a high hp application:
Walbro Fuel Pump Flow Figures Additionally, absurdly high fuel pressures can cause injectors to go static.
If you can electronically control the tune, and you have injectors sized correctly, there is no need for an FMU. Whether you have a stand-alone like the megasquirt, F.A.S.T., BS3, or AEM or a piggy back like the EEC-Tuner, Tweecer, or Quarterhorse. If you can electronically control the tune, then you should be able to more accurately tune to all engine rpms and loads, and you'll be able to do it without unnecessarily high fuel pressures.
Don't waste money on 2-gallons of race gas per tank. If you're confident in your tuner, there is no need for this expensive insurance. It would just be a waste of money. Tune conservatively and drive confidently. If your tune is safe, your motor will be.
Chris