All I got from Lutz's comments was:
- The car we originally designed is too heavy.
- Whatever comes out next as the DTS/STS has to be lighter.
- The current platform is too heavy, so we have to lighten it.
- That's going to delay things a bit, especially as we don't have Toyota's money problems, we have ours.
So I can see the premium Zeta platform suddenly become more premium as they opt for lighter weight materials and probably lighten up a lot of other things -- seats, bumpers, etc. As Lutz has said before, every little bit of weight helps and shedding 400 - 500 pounds off the Zetas would be a very very good thing for mileage.