here's what you do, rent an angle grinder, mask up and paper the side of the car and have that rear lip off.
It's gotta be done, the lip is useless really, just helps dirt to gather and causes rust, take you 2 hours seriously. I was a little worried when i did mine but it's like cutting butter with a hot knife.
make sure any exposed metal or gaps are covered in sealent (i used two coats, 1 of spray sealent and 1 of brushed sealent) otherwise it'll rust quicker than a spanner in a tropical downpour.
ave' a go, you only live once! :upside: