one thing to keep in mind is that on the lancer the vg's are there to direct the air towards the rear spoiler. VG's add drag to do this so while they may succeed in makeing the airflow follow too steep cuve the energy it takes to do this might offset any gains made by the smaller wake...
another thing that you might consider but might be difficult to simulate due to it's size is a small ridge just ahead of the trailing edge of the trunk. a good example is the reworked chevy volt, but i've seen similar setups on more conventional cars. on some cars a slightly more aggressive version of this is referred to as a gurney flap, although i'm unsure if it actually behaves like on an if it serves the same function as the ridge on the volt
some other low drag cars have a slightly up swept spoiler lip wich could also be related.
since its something relatively easy to fit it might be worth haveing a look at in case it's usefull
perhaps you'd like to test this idea also
http://ecomodder.com/forum/showthrea...html#post60227
it might be nothing but i'd sure like to see what it does compared to the rest
i wich i had suitable software for this sort of testing so i could try all my crazy ideas