As far as car/track combos I'll get the ball rolling and mention that I have all the Road cars and tracks and would be willing to race any of them, on Oval side I only have the cars up to the truck and Bristol, Indy and Daytona but I'm pretty much game to try any track, though I really suck at ovals.
As far as suggestions it seemed like some people had a hard time with the fixed setup so might want to avoid that, but I think sticking with some of the low class cars is a good idea to get people who haven't bought all the content to participate.
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--John
i5-2500k@4.8ghz, Asus P8Z68-V Pro/Gen3, 8GB G.Skill@1600, Noctua D14, X-Fi TitaniumHD
MSI 560Ti/448OC 1280MB@900/1800/2250, 3 x P2310H monitors, HAF932, Corsair TX850, Win7x64Pro
TrackIR4, Saitek X52Pro + Pro Rudders + Cessna Trim Wheel (sim flying)
Fanatec GT2 + G27 pedals (sim racing)
PSN/XBL/Steam/EA/ProjectCARS: Kludger
iRacing/rFactor2: Joao Silva