I just had an interesting incident in my E55.My 18" left front tire developed a bubble. I was about 200 miles from home. I called MB only to be told that no dealer in a 75 mile radius had a tire in stock. Not only is there no spare,the "tire-fix kit" is "not to be used on a flat tire"(in the owners manual,for real!) MB told me that it would take 2 days to get the proper tire(Conti MO) Ive had this problem years back in a Mazda twin-turbo,when a 16"tire was considered exotic,but at least Mazda gave you a spare,albeit a donut type. The problem then was that there was no place to carry the flat tire mounted on the rim in the car. Has anyome else run into this problem? Needless to say,I now carry a 245/40-18Conti MO on an AMG wheel in my trunk. It will fit front and rear on E55,but is is a rather inelegant solution. Also adds #s to car and eats up space in the trunk. I know that flats are rare these days,but if you own a 2003or 4 E55,PLEASE be aware of this potential problem.