Wilhelm, I've been using a BootBag with my 4/4 for the past year, and I am very happy with it. It is very strongly made and has plenty of straps to secure it to your luggage rack- it even comes with a large piece of soft rubber mat, which would be used to protect the paint on a car without a rack (MGB,TR4 etc). There is also a detachable shoulder strap to help with carrying the bag into your hotel. The zip has two sliders, which could be secured with a small lock to prevent casual tampering.
I hope you find these comments useful in making your choice. Best wishes, Gerry.
