I ordered mine with the dual receiver but have not really used for diversity reception. My K3 is used almost exclusively for contesting and DXing and the 2nd receiver was invaluable when it came to working Amsterdam Island.
I just think it puts the radio in the top tier of rigs when it is equipped with the 2nd receiver. However you intend to use it, you'll love it. Don't forget to match freq offset in the filters if you stay with the five pole filters.
BTW.....Love the call,