i used them in my mustang 5.0 and they went bad in a short period of time so i will never use them again.then i went out and bought NKG iridum and my car has ran great everysince. i also was told by a macanic that my car was one of the best running mustangs he has run acrossed.
i did before and they really didn't help it that much, i got better performance form a set of motor craft platinum plugs than i did from the BOSCH,they run good in some vehicles but a ford isn't one of them,go with the motor craft platinum plugs they perform real good and do really good on gas also,good luck.
If gaining HP is what you are looking for, my advice is to consider NGK, Splitfire Triple Plat or Denso. They are all better quality than Bosch and will have higher tolerance and give you better performance.