Scince you're only allowed sports tyres there's no point in going for as much engine power as possible. You'll rarely be able to get all the power down to the tarmac anywyay, and the car will behave very wildly on corner exits, with risks of spinning or running off the track. I focused on tuning the car to the get as most grip as possible instead, and here is what I did:
I added ballast to the rear until the balance was 50/50. Then I set downforce to maximum and finally decreased engine power until I reached the maximum allowed PP. On the first lap I beat the gold time by 8 seconds.
When driving, make sure you're always in control of the car. For instance, if there's a fast corner where you could go full throttle but there's a risk that the car could lose traction, just quickly tap the brake before the corner to shift weight to the front of the car, which improves front end grip. You'll lose a few tenths of a second in time, but scince the track is so long it's better to be safe than sorry, because it's a pain if you have to restart a lap when you make a mistake 6 minutes into the run. There's no need of flamboyant driving or corner cutting, just slow and steady, focus on hitting the apex right. Slow in - fast out.