Are Pirelli and Metzeler the same company (or owned by the same company)?
Pirelli bought out Metzeler a number of years ago and rumour has it that the Supercorsa pro's and Metzeler Racetec are made on the same production line.
The difference in tread pattern is purely 'marketing' and the Metzeler Brandname remains as it's still held in high regard in important markets in Germany and Eastern Europe.
I've mixed and matched SC Pros with Racetecs for years without problems (and the earlier Rennsports/SC's)