Would you need a rear wing to equalize the downforce?
I remember GK saying the GTS makes about:
100lbs of Rear Downforce
25lbs of Front Lift.
I forget at what speed though. I'm thinking like 100 mph
If you add a splitter that gives you 125 lbs of Front downforce then you would be equally balanced with the rear (-25 + 125 = 100)
So, 100F & 100R would be 200lbs of total downforce.
I do not think that GTS-R-001's talk about rake creating downforce at the rear applies to a stock car but rather more so to a modified car with more underpanels and a functional rear diffuser.
Underneath the backend of the Gen2's rear bumper is a pretty big cavity that traps and turbulates some of the air exiting the rear.