I am just about to buy a 2003 SLK320. At present it doesn't have a collapsible spare wheel only the tyrefit canister. If I remove the storage box will a collapsible spare fit in its place? If so, are the collapsible wheels for the R170 and R171 models the same? Or maybe any other models as they seem to be easy to source on eBay. Thanks in advance for any helpful replies.