I have a set of Philips Vision Plus H7 for '00 E430 and H4 for '94 Lexus LS400. Philips claims that Vision Plus generates 50% more light due to using Xenon gas. The light is a somewhat whiter and much brighter compares with standard Halogen bulb. I paid $40 for H7 and $28 for H4, shipping included. I bought these bulbs from autolamps-online.com.
I am not sure if Sylvania Silverstar is the same as Osram Silverstar which also generates 50% more lumens than standard halogen bulb. Both Philips Vision Plus and Osram Sylverstar are not available in North America. If you like to see the road better at night, Philips Vision Plus H4 at $28 is a better buy. If the appearance of your headlight is more importance, Sylvania Silverstar is for you.