I did some homework and found out that:
1. Swing weight doesn't mean anything if the static weight of the club doesn't allow you to achieve your normal tempo. Let's say, some crazy guy can make a club with a swing weight of D5 but weight 500 grams, now try swinging that, I bet you will feel like its swing weight is off the chart.
2. Swing weight is all about balance, it allows you to feel the clubhead, this confuse me first, but I try hitting the ball with the club holding backward and understand, you need proper balance of the club to swing it properly.
Then again, I find it very very strange that none of the manufacturer that I know of openly state the club weight of their driver on the specs sheet.
Why do I care about this, you may ask. Here's the story...
I'm 5'7", and weight 114lbs, I'm slim, as you can tell from my avatar, and my physically strength is, well, weak. I can hit the irons very good (for a newbie like me) and have great confidence hitting thems, but I can't drive, I just can't. The best I can manage to hit the ball straight is like 180yards, 10 yards further than my 4 hybrid. No matter how hard I try, slow and easy, hard and fast...
Yesterday, I read around the internet and found a thread on another forums, a guy complained about today drivers being too light for him, he need to increase the static weight to around 330 grams to swing properly, then I weight my driver, wow it's 324grams. Earlier, today I went to the driving range and borrow a driver from the pro shop, it's Cobra ZL or something that weight 310 grams (I brought the scale hahaha)
After warming up, I tried some drives, after 3 or 4 slices and hooks, I managed to hit 3 in around that go straight to where I aim, the balls drop right before the 200 yards mark and roll some more.
What I noticed is, my tempo is greatly faster than with my driver, although it is not as fast as with my irons which I feel comfortable with. I then ask to try hitting the Cobra Long Tom, which is 269 grams. Let's not talk about the accuracy, it's a 48" long driver, but my tempo is achieved, or I believed so at least.
Then I leave with a $38 more in the wallet, my old driver is with the pro shop now and I'm looking for another driver that weight around 270-280 grams. Maybe I'll buy something that weight 300 grams, widely available, and then cut it down 1.5" and regrip with Winn Lite 22 grams grip. Same swing weight, save around 30 grams, shorter shaft, and no more confusing about my drives.