+1 And the sounds it makes when you up shift without letting off the gas are incredible. I've had Porsche, BMW and Audi cars with double clutch transmissions. They may be faster but they are not as fun to drive. A 355 F1 is much closer to a manual than it is to a double clutch. Of course I haven't driven a 458 yet.
My experience with a 360 pump in a 355 is that you are correct. I can't tell the difference. I replaced mine because it seemed like it was about to go out. Sometimes when the car got really hot I had to hit the switch more than once to get into reverse. Now that I have a 360 pump I never have any problems. I don't notice any difference in shifting though.
I don't think the pump would make it any smoother unless your old one was not working properly. Just saying because mine is original and it shifts very smooth.