I think softer springs (as in this case red springs), are supposed to give you more grip than the hardest springs (blue springs in this case). The yellow springs are in between the two and give you a mix of both setups.
This is what I use each spring for:
-Softest/red springs-circuit racing involving more tight turns than straightaways.
-Medium/yellow springs-circuit racing that combines a more even mix of turns and straightaways.
-Hardest/blue springs-drifting, drag racing.
Of course, most people prefer a combination of springs to get the performance that they feel the most comfortable with. Those are just my preferences up above and you may see differently. It just takes trial and error to find the recipe that you will feel the most successful with!