BMW plans to introduce the core models of the M3 first:
Namely the Coupe and Cabrio . The next introduction would be a sedan which could debut at either Geneva or London 2008. The final model (for the European market only) will be an M3 Touring . And then a lightweight CSL model which would rely on further use of Carbon Fibre body panels in it's construction . The introduction and the acception of the M5 Touring in Europe has made this inevitable for the M3 Touring.
Because of reactions to the dollar and general acceptance BMW have no plans to offer both M Tourings in the USA.