Recently I changed my stock wheels/tire from 205 55/16 to 225 40/18 and I noticed that on the side wall it says 44PSI. I dont drive it everyday, may be on the weekend with dry sunny day. Should I keep it 44PSI or is it too much??

 

44 is the maximum pressure for the tire and it is not what you should be running unless you want a really stiff ride ..... the pressure recommendation for you car can be found under the gas door

 

If I used the recommand PSI for the new 18" wheels and with 225 40/18, would it demaged the wheels if I do a sharp turn without slowing down cause it looks flat at the bottom if I put in ~32,34 PSI??

 

no you wouldn't damage the wheel at recommended pressure but you can always add more air .... 44 psi is just really harsh riding