PDF to High-Quality .AI Conversion

I need three PDF files converted into .ai format. The converted files must maintain all details and have a high resolution of 500 DPI for large A3 posters or bigger. Requirements: - Preserve all fonts... (Budget: $10 - $30 USD, Jobs: Adobe Illustrator, Adobe InDesign, Design Optimization, Digital Art, Graphic Design, Illustrator, Photoshop, Print Design)