So now we're getting into 'usage case' differences. Off the line, a manual will always win (with proper technique), and since there's no power difference between the two and the fact that the auto ultimately means the power isn't put down as effectively, it will never catch up once behind unless the manual driver misses a shift.
So, in essence, a properly launched manual will always win, potentially by a decent margin depending on driver skill. An improperly launched manual will not win. It definitely is a case of driver skill and scenario, but when compared apples to apples with competent drivers, the manual has a noticeable advantage.
With that said, the overall difference will not be night and day (like a 911 version a 325i); the overall result will probably be less than a second apart over the course of a quarter mile. So, it all depends on what you want to use the car for.
For auto-x, an auto is unacceptable if you plan on being competitive, because you're giving away valuable time at the start line since you can't get as good of a launch. In ANY other scenario, however, the difference between the two is negligible.
In terms of pure shift speed in a scenario where let's say you're on a time attack around the track, the manual is still better because you can shift it faster if you put a little effort into it. It'll be a very small difference, but in a time attack, every millisecond counts.
Any street scenario that doesn't involve stop light racing is pretty much a toss-up between the two, and usually gives a nod to the auto in terms of overall drivability. The autos shift smoother under normal driving conditions, and around town, nobody is going to be speed shifting a manual, so overall around town an auto is peppier if you have a heavy foot. Let's also not forget about how much easier it is to take off at a light while, let's say, making a left. You don't have to worry about breaking traction, which could cause a problem when there's oncoming traffic, allowing you to quickly zip through without all the jerkiness a manual requires for a "quick" getaway.
They both have their advantages. For TIMED performance driving, get a manual. For anything else, an auto is just as good.
I have driven a Step ZHP and was perfectly fine with its performance, just for point of view. I like the short 2nd gear because it allows for some quicker acceleration. I have not driven a regular 330 automatic, so I can't compare.