Standard chips are very few and far between, tuners may be able to help you (i.e. MSD) as all the "Tuners calibrations" are copies of the Ford map anyway.
Also it's not a simple case of changing the "chip", you need to know the spec of you engine and have a calibration to suit, even if your car is stage 1 with it's current EPROM, it's best to get a tuner to check it over afterwards.
You may want to book a RR session in the first instance anyway, to see what it's running like.
Martin