If you are a professional trailer composer with a 64GB RAM rig, stick to Kontakt. You are paying for the scripting.
To install Shreddage X, follow these steps: shreddage x soundfont install
Make sure you did not move the library folder after activation. If you did, re-locate it. If you can tell me: What DAW you are using (FL Studio, Reaper, Logic?) If you are a professional trailer composer with