Not worth it in my opinion - and I own both a VX and a DI Axiom. Engine isn't noticeably more powerful, fuel economy isn't that much better (maybe 3-4 MPG at best). The Axiom does weigh 350+ pounds more, but even so I can't imagine the benefit would be anywhere close to the $$$ and trouble it would cost. Plus I think another member (iamironman?) already discovered that the 2004 DI swap wouldn't work (something about ECU incompatibility).

The dashboard on the other hand... I'd be the first in line for your retrofit kit if you could make it work.