Well you absolutely need DRL's disabled otherwise your car will ruin the ballast by not giving them full voltage during day driving.
I always play it safe and get a relay harness for each kit I buy.. regardless if it's a 35w or 55w kit. It's only $10 more and it's better to be safe. A 55w kit will require a relay harness. Some people say you don't need a relay harness for a 35w kit. It's up to you, but I'd be save and get one.
No need for an error code delete, our cars are not that electrically binded like some foreign cars are.
I noticed a stronger beam from my 55w kit as opposed to my 35w kit. They project more usable light since it's a stronger beam ya know. I doubt you'll ruin the housings, I have 55w in afermarket projectors and they are holding up fine.
