How to update the information in my "Signature"
 

My signature needs updating as to the Mercedes models I have and mileage, etc. but I can't find out how to do it.
Help please?

Up in the forum header click "User CP". When that window loads, click "Edit Signature" on the left hand side. It will bring up an edit box like you type replies to the forum posts in with your signature in it. Edit it as you see fit.

No idea if it'll work for you, but here's a direct link to the "Edit Signature" page:
http://www.peachparts.com/shopforum/profile.php?do=editsignature