Firstly, probably the standard tyres for that car. Secondly, Coulthard, a former formula one driver, span the car leaving Gambon.
Now, it's worth a few extra notes at this point. In, GT5 the standard tyres are Sports Hard grade. In reality, the car is a fairly hefty grand tourer and will need low wear rate tyres or it'll chew right through them a few hundred miles (or a couple of laps of a race track), but it's also a sports car so it will need grippy tyres to extract the maximum performance - so in the real world you'd probably describe those as "Sports Hard" (it actually wears Continental ContiSportContact 5P from the factory).
When it comes to gaming vs. reality, you'd expect the same person to be a couple of percent faster in the game than they are in reality, assuming a perfect simulation of reality and a similar level of familiarity. Why? In reality you have fear, you have limits, you have risk. There is no pause and restart in reality when you stack it and you can simply go much faster in the game because you will not die if you overstep the bounds. Gaming makes it easier to explore the limits. Added to that, go hustle a 2 tonne car around a track for 15 minutes - it's damned tiring. I did the same 15 minutes at the same time on my PS3 and I was fine - I imagine the guys at MBW had a bit of an elevated heart rate though!
Now I'm told that in practice, some of the gamers were hitting 1'12 - the gamers practised with Sports Hard tyres, but for the final event the tyres were switched to Comfort Soft. Even assuming Coulthard to be a bit over the hill (he's a retired F1 driver, not a current one), he's still someone who has been at the top of his game relatively recently and it'd be foolish to think you could drive a real car faster than him. That puts the gamers 6% faster on equivalent tyres - or it puts them in Pole Position while Coulthard is fighting the Hispanias... Dropping the tyres to Comfort Soft puts them 0.6% slower, or someone at the top of his game - Mr. Holland - 1.6% faster (with more than 15 minutes to do it!). This suggests that Sports Hards, though nominally the right tyre, have too much grip while Comfort Softs have a bit too little.
I think the problem is with GT5's tyre grading. It's done simplistically and for clarity - Comfort tyres are for commuter cars, Sports are for sports cars, Racing are for race cars, Hard gives little grip, Medium gives more, Soft gives most. A Punnett square of grip. Reality isn't like that. Reality has myriad different tyre materials (or compounds) which grip and wear at different rates - GT5 cannot give you high grip and low wear, but reality can. Reality has tyres engineered so that the transition from grip to slip is gradual or it could be a flat wall where grip vanishes. GT5 doesn't offer this. My hatchback-derived, wrong-wheel-drive coupe-style Japanese thing wears a set of sports tyres with a comparatively soft compound that wears well and a gradual grip-slip transition (I've put them on an MX-5 before too). You could call them "Sports Medium", but they absolutely would not offer as much grip as the SLS's stock tyres that we earlier described as "Sports Hard"!
GT5's tyre grading system isn't going to reflect reality properly. But this isn't a bad thing - it's still a game, any way you cut it. Unless they're willing to get into specific manufacturer tyres, with compounds, footprints, sidewalls and performance temperatures all simulated properly, you're not going to see reality reflected in tyres. And then what happens when Pirelli find out that GT9 simulates Toyo's Proxes T1-R to be overall better performers than their own P6000s? Back to square one...