Been thinking about the two wing thing with the subaru body, had a little play around and then noticed a something.
Basically I was looking at the interaction between the underside of the wing, and the almost Gurney like flip-up on the body-work. So I placed both wings in two different positions on the shell, in full back, and full forward. These positions were determined by the 3 holes on the wings as supplied.
I then applied some basic airflow thoughts to this, so decided to take some pics and show what I thought
Straight wing (large, almost perpendicular angle), in rear most position
What you see see here is the (simplified )airflow coming off the roof, and going under the wing, hitting the gurney, and then basically being flattened again. This means that the airflow underneath would not be providing an assistance to flow, and not utilsing the bernuli affect (air flow travelling a further distance travels faster, and hence is at a lower pressuer. This is the affect all wings are able to work by. Technically an RC cars "wing" is more of a spoiler than a full blown wing)
2) Straight wing Forward
Less straigtening of the underside flow here, however in the centre of the wing, due to the gurnery being curved and the wing straight, it could be assumed that the gap is suitable for smooth flow to take place. (also helped by the upward step in the middle of the wings)
3) Curved wing Back
Here you can see a good gap between the wing and gurnery, no flow restriction, and would deffiently help to aid the flow underneath the wing. This is especially apparent in the slot gap (where the wing and gurney tip are closest), as the air here would be accelerated, whilst still being relativly smooth.
Also note with the curved wing, as the gurnery is also curved, it would be consitent along the span, unlike the straight version.
4) Curved wing Front
Final pic. There is a Mahoosive ( :P ) gap between the wing and gurnery. What will happen is that the airflow nearset the gurnery simply wont have an sufficent affect on that nearest the wing, and as such provide very little acceleration to it. Not too useful, given the angle of the wing, but better than blocking it off (a la the straight version)
Having had a quick little mull over this, I think it'd be pretty reasonable to say that the straight wing will geneate more downforce, as it has the bigger angle, on it, even though the underside is pretty much doing nowt.
I would expect the curved version to probably be slightly nicer to drive, as it it would seem too be a more efficient wing, as the underside airflow would actually be contributing to the d/force generation.
For each, I would run the straight one in it's forward position (pic 2), and the curved in its rear position (pic 3), as these positions pretty much produce the best slot gap that they can, and then tune the chassis to suit.
Of course I cold be completely wrong on this, but until I've tried it out, this is my best guess. I am gonna try changing them this weekend and see if i notice a difference.
Anyway, though it'd make interesting reading.....
Oh and here's a couple of pic's of the complete shell