Sebastian Vettel has warned Lewis Hamilton what will make the seven-time Formula 1 champion’s move from Mercedes to Ferrari ‘difficult’ ahead of replacing Carlos Sainz. The Scuderia stole a march on the 2025 F1 driver market by signing Hamilton to a multi-year contract in February. A chance to steal the 39-year-old was too enticing for Ferrari president John Elkann, with the Maranello giant already having a vacancy with Sainz’s contract ending. Sainz has been a Ferrari driver since the 2021 season and is also the only non-Red Bull driver to win a Grand Prix since the 2022 Sao Paulo GP. The 29-…