I'm not really sure. You'd have to look into it, I never bothered leaving my DRLs enabled. And no, you don't have to use a relay for HIDs, you would only have to use a harness if you're going bi-xenon. But if you got the halo headlights, high and low beams have their separate bulbs. You could run a relay with a harness to prevent flickering, but I would only bother with it if it actually DOES start to flicker. I never had that issue so I ran the HIDs straight from the original harness to HIDs. And why are you trying to keep your DRLs again? Are you in Canada or something?