Difference between 55SR and 55X?

What is the difference between the 55SR and 55X? Is it altitude preselect and ILS approach capability? Is the flight director available for 55SR? If there is a flight director and a 55SR installed (and 55SR does not do ILS?,) does the flight director still “fly” the ILS?

I don’t know what the “SR” stands for but in general, the difference from the old 55 and the newer 55X is that the X model has internal GPSS (GPS roll steering) built in.

If perchance you are referring to the SR22 and SRX, it is primairly the SRX is a very stripped version of the SR20, without a lot of the avionics and the wheel pants. I think it was aimed at flight schools to try to get into the initial training market or as an first airplane to feed people into the step up market.