Completely untrue if you ask me... I put aftermarket wheels on and it had exactly the same stopping power as before.

If you want the brakes to be better, put in Racing brake fluid (so it won't boil, like Motul 600) and high performance pads (Such as Porterfield R4S compound for the street, low dust. Rotex Gold pads are ultra low dust, but I can't report on their better or worse friction statistics).

These two things together will make it stop even better with no fade if you take it to the track.

Lastly, if you want better response from your brakes, think about the braided steel reinforced brake lines that are available. These will eliminate the 'sponge' factor almost completely (unless you have air in your system).

Maintenance note: Change and flush your braking system like you change and flush your cooling system or at least half as often. Most people don't realize that brake fluid WILL break down over time and become less effective. This will also reduce the corrosion in your braking system.

Hope that helps... Cheers!