Firm Feel is the only one I know of that sells handling components for a C-body. But IMO, a C-body will be nowhere close to your MazdaSpeed3, especially if you're only going to ride on 16" wheels at the biggest. First off, there's hardly any tire availability with 15 and 16" wheels. You'd need to go to a 17" wheel minimum, which don't look bad on C-bodies as they're so big, but even tire options are shrinking for those.