Advice on some 107 wheels found at a junkyard

[matt7531]

I came across a burned 81 380SL in a junkyard. The wheels on the car looked unscathed by the fire. It is hard to make out the stamping, but it looks like they were made by "Lorinco" or something close to that. They are alloy wheels, not the bundt type but like the stock alloys found on the later models. The rear wheels have about a two inch offset to allow the mounting of a wider tire. The junkyard wants $240 for the set. First question - will the wider rear tires kill the gas mileage or otherwise cause problems if mounted on a 84 280SL? Has anyone heard of this brand of wheel before? What is the best way to deal with the mag locks if the key is lost? Thanks

Matt