i added the VGs last year for the primary purpose to help blow rain off the back window. As only the out edges would blow away, leaving a large separated bubble taking up most of the back window & making hard to see behind me. I added the VGs & anything over 45~mph my back window is damn near dry! But is it hurting/costing me drag? Should I remove the spoiler?
As the car is getting faster & faster, Ill need to add aero to improve grip...i also want to help make the car a little more slippery if possible.
I plan to make a front splitter with an extention to the firewall. I also have a rear diffuser that i'd like to install to help with grip & stability along with smoothing out the whole under trunk area to remove the open voids.