It's very difficult to butt match a color that is 15+ years old. Luckily for you, your red is a solid color and not a metallic, like
@Alex01 's. Those are super tough to butt match. Body shops cheat and blend the paint into the adjacent panels to give it the appearance of a good match, then clearcoat the entire panel to a break line. What will help you the most is polishing the adjacent panels as well as the doors. Doing so will bring the pop back in the tired out and faded red. Other than black, red is the worst at fading over time.