Hi, Aitor,
As Chris said that you could use KDS tools and MCUXpresso tools to develop code for KV58 and KSDK is a software package.
If you use KDS tools, you can develop code without KSDK package, in other words, you can write peripheral register directly without using driver of KSDK, the KDS tools provides the peripheral register address in a *.h file so that you can access the peripheral register, furthermore, the KDS can generate the initialization code and vector table withour KSDK. In conclusion, KDS tools can work with or without KSDK package.
If you use MCUXpresso tools, you have to use KSDK to develop code.
When you download KSDK, the KSDK package will direct you to selcet the tools KDS or MCUXpresso.
hope it can help you
BR
Xiangjun rong