No, I'm running 6mm up front and 20mm in the back. It's been running great for the past few months now, and no issues at higher speeds on the freeway.
The 15mm spacers won't fit on the factory 20" performance wheels (lots of posts & pics about this), so I'm running 6mm spacers for a Honda Accord, as it has the same bolt pattern & CB size as my non-performance Model 3.