I guess a serious answer to your question would be:

Performance wise an auto will shift just as quick as a manual. Most modern autos allow you hold the car in 3rd gear for quick downshifts into 2nd for rolling acceleration. The main problem comes with launching automatics; most OEM torque converters dont have a high enough stall speed so you bog off of the line since you're launching at 3000rpm or so. Most automatic cars can pick up at least a half second at the strip with a new torque converter. Launching is simple and consistent.

The downsides are that torque converters tend to lose some power unlike a clutch which is a direct connection to the engine. You can get locking torque converters but these can reduce the reliability of the TC as well as the tranny. The other big problem is that heat kills automatic trannies, if you're running big power (or even moderate power) a transmission cooler and some good auto tranny fluid will be detrimental in keeping your transmission alive. Be sure to let the tranny cool down between hard runs and it should last you a while. In order to make the transmission hold more power you must increase the line pressure to the clutchpacks. Some cars let you increase the pressure with electronic controllers (I know 300ZXs have this), others you must swap in built valvebodies and high performance clutchpacks.