I ran a 780 with SB cyl and concave with high speed rotors next to a stock 780 all year. Where there is a difference is late at night or in tough conditions running slower cyl speeds. Definitely can push harder with the SB components in those conditions, but not sure you would see 10-15% on average even then. When dry I don't see a difference and we actually felt like the SB cyl cracked a bit worse than the stock cyl.
I plug my impeller once per year so far, usually pushing my limits. I think a SB impeller would help with that. The caps look like a good thing to try for a moderate cost. Where you will see a big gain is with the high speed rotors in cereals, I would be swapping mine out if I didn't already have them or if I was buying a 760.
AN ERROR DOESN'T BECOME A MISTAKE UNTIL YOU REFUSE TO CORRECT IT
Orlando A. Battista