I haven't had to use impact tools on my Mercedes, but on my Dodge truck they were almost mandatory. On my Dodge, an impact wrench alone wouldn't free the lower ball joint castle nut. Nor did spraying it days before with penetrating oil. I had to use the impact, then penetrating oil, then impact, ... I would suggest using impact tools for REMOVAL only. If it goes on THAT tight then either something is incorrect or it probably should be torqued accurately.

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Brian Toscano