As for everything else, don't blame lap times on the car. Go out there, and drive your car until you've not only reached the max potential of its current settings but have also developed enough as a driver to be aware of everything and able to properly translate a lapping day into knowing what kind of adjustments need to be made. This comment is more aimed at suspension/handling/dynamic adjustments but just in general. Experiment more with stuff like early/late/trail braking, heel-toe, throttle control, line of attack, etc. THESE will make you a better driver. Don't be afraid to spin your car out or lose control. If you drive with fear, you will never drive well.