My analysis of this valve spring showed that it`s a game changer for any automotive enthusiast. The increase in performance and power is noticeable from the moment you start driving. The quality of the material and manufacture is top-notch ensuring dependability and reliability for your engine. The only con I found is that it takes a bit of time and experience to install, but the results are worth it .Overall, i highly recommend this product for anyone looking to upgrade their car's engine performance..