This vid shows some conflicting results but it is the method I intend to show. Not the results. Malossi is all over the place on colors. The white/Yellow are the weakest of the malossi's Then it is green/purple/blue/red. Red is strongest.
You will lose notiing in speed but you may have to go to heavier rollers to control the increased rpm's from stronger springs. I just yesterday installed a Malossi Purple, and white fly springs in a gy6, and it is now doing burn outs on any loose surface. Never did that before. My wot rpm's stayed the same using DR Pulley 7gr sliders. I may try 6-6.5 gr next, and blue fly springs to bring up the launch rpm.