Has anyone fitted a set of these to their car? http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=72220&item=7955534087&rd=1 If so, how easy is it to remove the existing ones? Do they simpy unscrew? If so, they must be bl00dy tightly screwed in, is all I can say! Anyone out there who can help?