Our valve springs are custom made to be 50% stiffer than stock. They are not just springs from another engine and are a direct fit. No modifications need to be done for them to fit. 
 
If you are running more boost and/or high RPM's on your OM60X, it is highly recommended to upgrade your valve springs. Otherwise, you will likely experience valve float, which can damage your engine. The stock springs can't handle much over stock boost and stock max RPM.