Usually most people who have found it missing haven't noticed any change in noise or performance etc and simply discover it missing when they check so definitely best to check it every now and again.
It is definitely worth getting the upgrade sorted - if your local dealer is nice they will do it free of charge, if not then the parts cost about £10-15 depending on where they are sourced from and if you have some tools then its easy enough to do yourself. If not a local garage should be able to do it for say half an hours labour. Even then, there may be some helpful foccer locally who will lend a hand
Unfortunately, I don't have the part numbers / service note to hand but they are listed in several threads and there was one fairly recently which went over the entire problem which I guess you read.
Where abouts are you in the world?
And welcome to the forums ^^
