Cars need more bulbs than most people might imagine. Headlights and rear lights are the most obvious contenders, but there are more.

When it comes to headlights, there are a number of options. However, two of the best headlight bulbs are the Philips D5s PK32d-7 and the Osram D8S Xenarc Electronic 66548. Both are Xenon HID 25 watt bulbs, but they have some differences.

The similarities between the two.

Both light bulbs come with a one year warranty, and they are both free of mercury, so they are safe to handle. All light bulbs which come from these two lines are legal for use on the road, and they also are ECE certified. Since the headlight bulbs have a particular colour to them (they are very similar to daylight colour), the manufacturers recommend that the bulbs should be purchased in pairs. This is so that car owners have replacements on hand when their bulbs burn out, rather than needing to have mismatching headlights. The bulbs simulate the brightness of daylight when they on, and so avoid any of the problems which come from having bulbs so bright they can disrupt other drivers on the road.

The differences of the Philips D5s

The Philips D5s bulb has a lifetime of 2500 hours, and it is very easy to replace a bulb when one burns out - simply plug the new one in and you are good to go.

Part numbers of D5S:

  • Philips: 9285 410 171, 9285410171
  • Philips: 9285 409 171. 9285409171
  • Audi: 8W0 941 235, 8W0941235
  • KIA: 18647 25012, 1864725012
  • GM: 13594523

The following cars are using D5S 25W bulbs:

  • Alfa Romeo 4C 2013, 2014, 2015, 2016, 2017, 2018, 2019
  • Alfa Romeo Giulia 2016, 2017, 2018, 2019
  • Audi A3 S3 8V 2016, 2017, 2018, 2019
  • Audi A4 B9 2015, 2016, 2017, 2018, 2019
  • Audi A6 4G 2014, 2015, 2016, 2017, 2018, 2019
  • Audi Q3 8U 2014, 2015, 2016, 2017, 2018, 2019
  • Audi Q7 4M 2015, 2016, 2017, 2018, 2019
  • Audi TT 8S FV3 2014, 2015, 2016, 2017, 2018, 2019
  • Audi TT 8S FV9 2014, 2015, 2016, 2017, 2018, 2019
  • Citroen C4 Grand Picasso II 2014, 2015, 2016, 2017, 2018, 2019
  • Citroen C4 Picasso II 2014, 2015, 2016, 2017, 2018, 2019
  • Fiat 500X 2014, 2015, 2016, 2017, 2018, 2019
  • Opel / Vauxhall Corsa E 2014, 2015, 2016, 2017, 2018, 2019
  • Skoda Rapid 2014, 2015, 2016, 2017, 2018, 2019
  • Skoda Superb 2015, 2016, 2017, 2018, 2019
  • Chevrolet Silverado 1500 2016, 2017, 2018, 2019
  • GMC Sierra 1500 2016, 2017, 2018, 2019
  • GMC Sierra 2500 HD 2016, 2017, 2018, 2019
  • GMC Sierra 3500 HD 2016, 2017, 2018, 2019

The differences of the Osram D8s

The colour temperature of an Osram D8s 66548 bulb is 4500k OEM standard. Bulb's socket name is PK32d-1.

The Osram D8s is definitely compatible with the following list of cars:

  • VW Amarok 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017
  • VW Beetle 2011, 2012, 2013, 2014, 2015, 2016, 2017
    VW Caddy 2016 2018 2019
    VW Touareg 2016 2018
  • Kia Forte 2014, 2015, 2016, 2017
  • Ford Focus 2012, 2013, 2014, 2015, 2016
  • Ford Mustang 2015, 2016, 2017
  • Hyundai Santa Fe 2014, 2015, 2016, 2017

Part numbers of D8S:

  • Audi / VW: 8R0 941 235, 8R0941235
  • Audi / VW: N10815201

There are, however, many more car makes that are compatible with the light bulbs. If you are unsure about whether or not these bulbs would work for your car, you should get in touch with the manufacturers, make comparisons between the parts shown and the parts of your car, and check the parts numbers.