i have been going through this. i dont even have a fmu. everyone is going to tell you to get the car tuned and ditch the fmu but yeah if u dont get the car tuned, you NEED to use it with 30 pounders. Im getting 42 pounders and a tune next week. i tried to run my car with 24's and no fmu and all it did was ping and pop and not go. so i parked it till i get the upgrades. i have an s-trim 10 psi. what do you have?