What is the best (per your opinion) replacement bulb for 2006 S60? Son wants a HID, but I'm not sure if this is a plug and play replacement. Any insight will be appreciated.

 

Since the 2006 2.5T did not come with HID's they are not a plug and play replacement. To my knowledge, you will need to create a custom wiring harness for the headlights as the pins are in different locations and also a potential software update to make the CEM work with the HID instead of halogens.

However, if you wish to tackle the task, I have a set in good condition sitting in my garage lol.

For a bulb, I honestly just went with these below. Sylania is also good. Best way to improve the headlight visibility is to clean and polish the lenses (plastic) or get new assemblies if they are in bad shape. I had to get new assemblies when my finger went through the plastic housing while changing a bulb. I bought cheaper TYC ones off ebay with no fitment issues.
https://www.fcpeuro.com/products/hal...rmance-2-0-h11

 

Thanks! That was my inclination!

 

I tried to just do a swap and a software update (dealer tried, my local indy probably knows better for stuff like this) and it still wouldn't work. I did notice the pin difference when plugging them in. I will say though, the dealer did something to my car because after they did their R software updates, my car was running 12/13 PSI instead of 7 PSI peak for intake pressure! Free tune