Nope, IMO thats a waste of time as all your gaining is the extra leverage of having a larger diameter, your not even using the full surface area of the disc!
If you do it properly and fit the ST Calipers, pads, and discs the breaking is far far better! Just need to drill out the hubs to take the larger caliper bolts and fit 12mm spacers to center the disc's

Just want to know what people use for the 12mm spacers of where you can buy them?