Re: KO Digital Progrmable servo
You can program the endpoints, speed, etc. but you need to buy their programmer in order to do those things. The real value (imo) of a FET servo is the precision and speed of it. Once you try a FET servo, you won't use anything else. I would actually recommend going with the 2123 since it's faster and runs off of 7.2V rather than 6V from the receiver's power. There is an extra blue wire that you attach to the blue wire on your esc, if you have one, or the + power lead on the esc, if you don't. It has the same programming features, just 7.2V.
I own many Futaba, KO, Hitec and Airtronics servos of various models. The only ones I use as steering servos are KO PDS2143 (old version of the one you're asking about,) 2343 or 2123. In my area, KO servos are also a bit less expensive than Futaba. I hope that helps.