Well this question can be made easier from the following fact.
The Duet will be automatic while the Liana RXi will be manual.
So the obvious answer would be LIANA RXi. The Liana could use the gearing more effectively than the Duet. Hence, it would outrun the duet (even if the driver of the duet was better than that of the Liana).
Thats my opinion bro. You are entitled to your opinion.