The preformance package was offered later in the life cycle and i think you got a little more HP out of the box (they didnt offer it in a coupe at 1st becuase they thoght it might cut into m3 sales, but later you could get the coupe with it), and a different front facia, maybe some bigger wheels. I dont know if they did anything to the suspension that was better than the sport package.
check out the link for more info
330ci Preformance Package