It's not a big deal. The sender is at the top of the tank so the fuel level doesn't have to be all that low. I R&R'ed these in both our 124s and didn't buy a special wrench, although I don't remember now what I used.

I thought the hardest part was getting the liner out of the trunk to expose the tank.

Just relax and do it.

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2012 E350
2006 Callaway SC560