The cheap 718 GT4 Aerodynamic upgrade Porsche won't tell you about 

These aerodynamic fins (coming straight from GT3) help reduce lift and manage tire wake. Unfortunately even though they come shipped with every GT4, most dealers do not bother installing them on the cars during the PDI process since it requires a good deal of work cutting outlined holes on the wheel liners and the under body panels. 9/10 other GT4 owners that I spoke with said they didn't have these installed on their car coming from dealer. Here's a how to make a little project out of these over a weekend.