show me your engineering skills if so!
Seems like you could semi-airfoil the back end of your stem/spacers with clever use of tape or something
i have made a few stems using aero tubing,you could alway get a small piece of aero tubing cut the front(nose) off and glue?? onto the rear of a stem.
What bodies do you race under?
Generally, it has to be structural to be allowed.
TJ Tollakson showed up at Kona with this setup one year. IIRC, he was not allowed to race with it as pictured:
Someone on the Cervelo Forum has made a carbon headset spacer for their P4/Ventus, it replaces the stock headset top spacer piece (don’t know the official name)but has the same shape as the Ventus stem airfoil and sits almsot flush with the top tube…very slick looking. Most stock pics of the P4 online show this but apparently only a few were originally made, I was told by Cervelo that Cane Creek will be making them at some point, might be specific to the P4/Ventus though.