Torque converter question

Will a high stall converter affect the performance of the tranny, other than from a dead stop? I understand how important they are in a performance build for getting the 'jump' off the line, but is that where the advantage ends? Or do they affect shifting as well?

I'm guessing a shift improver kit is the best way to slam gears, and that a TC won't have much affect at all on performance, once the car has gotten off the line(?)

Still a newbie learning this stuff, thanks for your thoughts.