Apparently Turn 10 Studios have finally been able to cut a deal with EA concerning the use of Porsche cars. EA currently holds the rights to use Porsche cars in console racing games, and Turn 10 owns the rights to Ferrari cars.
This means that sometime during this Spring, Turn 10 will release a Porsche Expansion Pack for Forza Motorsport 4 which will include "30 modern and classic Porsche vehicles". The only confirmed cars thus far are the 0210 Porsche Sport Classic and the 2010 Boxster S.
There's a story up right now on Jalopnik.com