I'm not sure it will make a difference.
From my experience, if at the end of 5yo season it's only won G3 races......they don't tend to be G1 horses.
If you are happy with your horse then I'd put it in the breeding barn.
Experiment with your breeding - especially if you have a good sprinting stallion - you may get stayers with more speed or you may get sprinters with more cruising burst. But sprinter together then you know what you are going to get