Audi A4 1.8 Sport Iggnition Barrel

Does anyone know if it is possible to change the ignition barrel and what is needed to do this? The car is starting intermittantly, and i
have been told it is probably the coil around the barrel, the car has an immobiliser and was wondering if changing the barrel will affect this? Any help greatly appreciated :)

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.