95CTburb19: Yes, the numbers are different sizes. For a 06 Chevy Silverado, the low beam lights were 9006 and the high beams were 9005. If you want to try the Silverstars you can however, you will be paying half the price of my HID's. I first went the cheapo route and bought generic bulbs that warped within a month of use. I'm not degrading the Silverstars, I'm just telling you your two options: buy cheap bulbs and pay a lot at first (HID) OR buy expensive bulb replacements and pay cheap first (Silverstars). HID bulbs are brighter, cooler (temp wise), and less expensive than Silverstars, with the only down side of $120 shipped on eBay versus $60 Silverstars at AutoZone.
I recommend HID's for any vehicle.