You should be OK, though of course the temperature in the car will likely exceed 35 by 5 to 10 degrees. The danger is not the electronics or connectors (which will get a lot hotter than that in use) but the plastics/ramps etc., but avoiding direct sun is probably enough of a precaution. You might consider taking the playfield glass off just to ensure less heat build-up, but again, if in the shade probably fine.