I did this but just stuck a heavily tinned-ended wire into the gap on the back of each plug.
The first LED bulbs were pretty good, but started to burn out after 3 months
http://dx.com/s/100619
Next these which also flickered after 3 months.
2nd
http://www.aliexpress.com/snapshot/224024448.html
These are even brighter, very OE look, but as soon as they are on, my DAB radio turns to bubble and squeak. They must emit some RF which is a big shame. The previous ones didn't despite looking similar. Glad I didm't start replacing radio parts, just found the damn radio started working fine when I turned ignition off and narrowed it down to the DRL.
3rd
http://www.aliexpress.com/snapshot/248859848.html
Maybe I'll they these next?
http://www.aliexpress.com/item/Hot-S...255378976.html