Two newbie questions

1. The optimum temperature is grey. Blue means cold, and red is hot, so in between is the best. Although you can run faster times by making your tyres red, although this is not good for long-term use, as your tyres will degrade faster.

2. Personally, I don't think there is a 'most important' component. Or, at least I haven't found one. It could be that a good front wing makes more of a difference than say the suspension, but I think there are too many factors to test this theory properly, as each track is different, and different drivers and cars will perform differently at certain tracks.

If someone's tyres are very red, then they're going to lose A LOT of performance VERY quickly, and will probably start lapping 2 seconds slower, if not more. So in your scenario, the guy with grey tyres at 70% would be miles quicker.

The key to race pace is consistency. You should try and keep your tyres grey until your upcoming pit stop, when you can probably push hard for the lap, and then again after to heat the tyres. If you're struggling on race pace against people who have bad tyres, then it could be that their cars and/or drivers are much better than your own currently.

EDIT: It could also be a factor in strategy. Tyres, fuel and how often you pit (as well as race distance) are all key factors.

Haha, yeah, that is a quick recipe of how to lose races :P - Good luck in your next race :D