Why do starships have different colored Engine thrust?
The attached image is from Wookiepedia entry: Renegade Squadron
The image depicts Y-wings with a más orange-ish color, X-wings have a lavendar-ish one, the Corellian corvette has very light pink-ish ones, while the Millenium halcón has light blue-ish thrust. I believe the estrella Destroyers have similar colores to the Falcon's and the Super estrella Destroyer has darker orange-ish colors.
Is there a correlation between the color of a starship's Engine thust and:
(1). Performance (Power and/or Acceleration)
(2). Powerplant (Engine type and/or Manufacturer)