You'll be fine installing that bulb, if it fits.
OEM bulb manufacturers play fast and loose with their ratings. It's not always about the "wattage" in terms of power consumption... sometimes they make an "equivalent" statement about perceived brightness.
In essence, they use different color coatings to shift the spectrum towards "blue", which may appear "brighter" to the eye and illuminates reflective coatings on road signs better.
Whether or not these bulbs are really "brighter", "safer" is a matter of great debate. Check out Daniel Stern's lighting page for and endless rant on this topic.
It all boils down to the color spectrum. Bulbs that throw more blue spectrum appear "brighter", but that may be because they are throwing more glare. Your brain perceives this to be "brighter", but only because the glare forces your brain to close your eye iris to some degree. According to Dan Stern, this really isn't as helpful as it would seem. "Yellow" spectrum of light provides greater actual illumination, allowing you eye to dilate more and get more information. The yellow spectrum is particularly helpful for dealing with foggy/snowy conditions. Blue spectrum bulbs tend to reflect a lot of extra light off the "fog", and seem brighter - except the fog isn't what you need to see clearly.
I know a great deal about this topic, and yet I actually know nothing. More TRUE wattage is always better, but you often have to order actual high-wattage bulbs through a back-door [often European] source. They are probably not technically legal, and your wiring/sockets may not be able to handle the extra heat and wattage such bulbs entail.
In any case, I see no problem in installing that bulb. I hope it helps. 5W is not going to make a difference. Your better solution may be aftermarket "driving" or "fog" lights - which will allow you to put another 120-200 watts of illumination out there. More bulbs are better; "superbulbs" may be a compromise and expense that doesn't achieve your goal.
