Hi Stephen, you're not crazy to think about selling off the Kongo in place of the Haruna. I've done things like this myself when a better version of a kit came along.
Unfortunately, I'm unsure of how well the Kongo's PE would work with the Haruna. I think a lot of it would be usable, but many items would be close but not quite right (railing lengths, flight deck items, ladders, stairs, funnel rings, etc.). There is also the hopeful possibility that Fujimi did a better job with the Haruna's PE set, just as they did with the kit (the Kongo's PE isn't very good all told). So aside from difference issues, the PE may be better in the Haruna set.
If I ever get my hands on that Haruna set, I'll post a review. Otherwise, I think I may see what the aftermarket comes up with...
Frank, I agree that those kits are the best car models out there- at least in 1/24 (Protar's stuff was pretty hot too). The first time I opened a 356C kit way back when, I was astonished at the level of detail- crank case, and everything. Whew! Went together like a dream... (looks up at the 356B roadster kit sitting overhead) Gyah, temptation!