Patch EHP4 SR1 (SP03) in an existing EHP4 (SR0) system

Hello experts!

We have an existing EHP4 System ERP 6.0 (SR0, without any SP).

We want do include SR1 = SP03 for EHP4. What is the right way?

- Download SP03 with the MOPZ

- Install SP03 with SAPehpi ?

- Install SP03 with SPAM/SAINT ?

Can i unse the EHP4 SR1 Installation DVDs to patch my EHP4 -SR0 system?

Is this "patch to SR1/SP03" comparable with the upgrade fom ERP6.0 to ERP6.0 EHP4? Or is this a normal SPAMSAINT patch?

Thank you!