The whiteness tricks the eye into thinking it's brighter. However, hyperwhite dome lights such as Polarg's do seem to light up the cabin brighter. Different filament, a tad higher wattage? I don't know and don't care...I think it's not worth the time and effort for me to research the seemingly superior performance of a dinky little dome light bulb!
Try
www.optauto.com but I think they are like $14.99/pair.
Anyways, my bro has brand new Polarg pairs for sale...$12/pair shipped (two free rap and/or R&B CDs included with every order). They are 3175 size, but will fit the slightly smaller trunk light of a 5G Civic (3022 I think).