Newby here with some questions

Hello!

New player here and i'm having a blast. By far the most fun i had in a sim. Kudos to the awesome AI, the physics and the FFB. The game is incredible

I have a few questions as a newcomer, so any help will be appreciated

1. With the GT3, under braking, the FFB shakes a lot, but with the RIGHT it doesn't happen It's that normal? It happens with both Ford and McLaren
2. I have some massive FPS drops in the middle of a race for no particular reason. When the race start, with all the cars, i get between 110 and 140 fps, but after 20-30 minutes of race, the FPS start dropping until 30-40 in the lowest parts of the circuit, and only got 60-70 in certain sectors. Why does happend? Why at the beginning with all the cars i get so much and then when i'm alone or with other cars the fps goes down? Same conditions, no rain or night
3. Is there any tutorial on how the NRG on the GT3 works?
4. Again, any tutorial on how degradation of tyres works? Especially for the GTE, which have different compounds and looks like they need more strategy than the GT3 which only have mediums

Thanks for any help!