(Tasteful) Body Mods for C6 S6?

Hey all, I was down at the Texas Mile this past weekend, and while my S6 didn’t make an appearance (still working on it… :’( :’( ) it got me thinking about what kind of aero parts are available for our cars.

Ideally: tasteful when attached, but readily removable when aero isn’t of concern (basically, not doing an all-out mile, 99.99% of driving time).

Anyone know of good places or done any of this kind of bodywork?