If you can stretch your budget, rFactor 2 is available on Steam. It improves physics, graphics, weather, and tire modeling. During Steam sales, rFactor 2 can be found for under $10.
That seemingly innocent ZIP archive could be a vector for severe security threats. Here’s what you’re actually exposing yourself to:
Legal Consequences
Ethical Considerations
Loss of Updates and Support
Less dangerous but still irritating: many "crack" downloads redirect your browser to shady search engines, inject ads into every webpage, or replace your new tab page with sponsored content.
If $15 is still too much, consider truly free, open-source sims: