Audi are going for an all State type approval for that very engine.
The reason thye are using the 3.0 TDI is its broad spectrum. It fits into and hauls just about every model platform. It appeals to the performance, eco minded and torque needy customer. Rumors abound for other engines but lets see how this one is received.

SIG

Bahia Beige 3.6 S-Line...22" VSR/Kohan
Blue Pearl (Special Order)
Calla White 3.6 4.2 S-Line 20" S-Line 21"
Cobalt Blue 3.0 TDI 3.6 on Chrome 20" 4.2 with step S-Line S-Line
Condor Grey 3.6 3.6 4.2(no S-Line pics)
Daytona Grey (only S-Line) Clear tailights
Garnet Red 3.6 4.2 S-Line 21" Clear Lights
Lava Grey 3.0 TDI 3.6 4.2 S-Line
Light Silver 3.6 4.2 S-Line 21" Clear lights
Mugello Blue 21" 20"(only S-Line)...22" Project Kahn Wheels
Papaya Orange S-Line 21" (Special Order)
Phantom Black 3.6 4.2 S-Line 21"...22" Replica 10 Spoke
Quartz Grey 3.6 3.0 TDI 4.2 with step S-Line Offroad...22"
Suzuka Grey S-Line 21" (Special Order) Clear Lights
Sycamore Green 4.2 (no S-Line pics) Offroad 3.6
*Interior pics* *Roof Bars pics here*