The Kelvin values supplied by serious companies providing LED conversion kits like IPF, Osram and Philips are fairly correct and can range between 5000-7000K. A 1000K difference is imho a pretty big difference that is easily distinguishable for the naked eye. If you care about matching the white lights from the LEDs on your car, stick to reputable manufacturers and buy the same colour temperature.So basically, pretty much any LED headlight will match my LED DRLs whereas, extreme halogens may seem slightly less blue. That’s helped a lot Thankyou so much
Bonus story: I bought a H4 LED conversion kit from IPF specifically because they could provide a kit with a 5000K white. A good looking light that is much less blue/purple than most LED conversion kits on the market. At a quick glance the whiteness of the IPF light looks a lot like the one you get from halogen H4 bulbs like Osram Cool Blue Intense or Philips WhiteVision ultra that has a blue cap/coating. Why IPF and why 5000K? Mainly because of two things - MOT and safety. Knowing I can drive my VW Up to the annual MOT without worrying about or revert my conversion. And being able to drive my Up at night knowing I'm not blinding oncoming traffic with my much improved light (stock lights are terrible). Using after market LED conversion kits in an ECE-approved car (that was originally sold with halogens) is not legal in Sweden and will normally not pass MOT over here. My car has passed MOT twice now with the IPF LEDs installed. Most likely because the light temperature and pattern doesn't scream LED like cheaper kits do.