On a standard GT3 car, I'd setup the pressure around (bars) 1,42 on the front and 1,40 on the rear. It obviously needs a little tweaking for long races, but it oftenly does the job.

But "too high by default" isn't always the case, when loading up the BMW Touring Car, I think it's setup such as front 1,55 and rear 1,30. I tried my GT-cars tire pressure (26 PSI when heated up) and I've experienced better laptimes (alongside other tweakings).