A6 C7 halogen to led retrofit

[joeblogs]

hi guys,

i have a audi 2013 a6 saloon se i have halogen lights fitted i am looking to upgrade the rear lights to sline i have been told i need a wiring harness. i have been quoted £200
for the wiring and the coding dongle. do i require the coding dongle as i have access to vcds. and can i not make the loom.any help much appreciated.

cheers
joe