Thats an interesting read and seems that it should be possible then. It was just something I was considering giving a shot. After all we dont truly know untill we try it.
The kia has a curved side as well. I may try the sharp edges idea and extend the roofline for a few runs.
The mitsubishi evos use vortex generators on the MR
JDM EVO MR Taillights Set - EVO 8/9*::*EVO 8/9 Exterior Parts*::*EVO 8/9 Exterior*::*Exterior*::*LancerShop.com | Lancer Evolution Performance Parts
A really good article here:
http://www.mitsubishi-motors.com/cor...004/16E_03.pdf
But for now its back to making some more smooth wheels after my first attempt disapeared. the undertray is complete and will be refitted after my master cylinder change. If I see an improvement then im going to remove the coroplat tray and mesh and fibreglass for a better finish.
Edited to add with a daily commute of 150 miles total every little helps