1) How well do the Drive cars work on Overdrive? I was considering eBay to buy a few Drive cars to round out my set for cheaper. I know they can't be used in Tournament mode, but I'm not sure what that is and if it's the majority of solo play.
2) If you could only get one accessory with your starter kit, what would you get? An extra car, a supertruck, the collission kit, what? Collision kit seems like the most fun after the complaints about the launch kit and having to spend a lot of time picking cars up..Yes the GEN1 cars work with overdrive, but there are some limitations :
GEN1 cars as sold have traction problems on overdrive track. they require you to work with Anki customer service to get tires made out of the new softer material that the overdrive cars are made from. After this they perform excellent.
GEN1 cars do not, and it appears never will, have access to their "signature" abilities from Drive.
All GEN1 upgrades are interchangeable between GEN1 vehicles and as such there is no difference between them. All 7 GEN1 cars are treated as one in overdrive.
As far as extras it depends on you preference. If you don't like cars leaving the track then you should avoid the launch kit, the collision kit, and the supertrucks as all three are designed to cause chaos. Adding additional cars or track are the safest way to add additional versatility.
I hope you and your family have as much fun as my family has. We have been playing it since Drive and overdrive always delivers a night of fun.
I enjoy the GEN1 cars just as much as the GEN2 cars, but they have less uniqueness.
I have all seven GEN1 cars all six GEN2 cars and the three Supertrucks and I like all of them.