The Canadian W450 799cc CDIs have 40 HP sure enough, but 74 Ft-Lb of torque, more than the W451 999cc gassers at 68 Ft-Lb. It is torque that gets you to speed, HP is only a derivitave that sustains speed.
The new W451 CDIs (still 799cc) are up to 45HP and 81 Ft-Lb torque, and will supposidely make EU5 requirements. Once EU6 goes into effect, they may not, and may likely only be sold in non-EU markets.
For the year 2009, US and EU5 standards pretty closely coincide. But in 2010, the US gets stricter again and the '09 window slams shut. I don't see the VW Jetta "Blue-whatever" making it with what they don't have (a BlueTec/AdBlue, aqueous urea anti-NOx system). The M-B E320 and VW Taureg are physically large enough vehicles to carry the full BlueTec/AdBlue package and they have the nationwide dealer structures to keep it going so they should be OK.