Vortex generators

I posted this under performance instead of vanity because I was wondering if the roof VG is any real help. I've mentioned before that my MR with the lip spoiler feels light in the rear on high speed sweepers. I've since gone with a coilover set up which has gotten it down out of the air some and helped, but I still worry about it happening again at some time because it is a scary thing to experience. I know the VGs have been shown to be pretty uneffective with the big wing but was wondering if there might be some real upside with the MR. I want a painted one, looks like the rexspeed is the only real option although I'll have to dremmel out the antenna hole, they're only $115 but shipping is like $50 unless anyone knows of a better deal.