An article on IndustryWeek mentions that by first optimizing the product with the company’s Design For Manufacture and Assembly (DFMA) software, the subsequent lean/Six Sigma initiatives can proceed from a more refined level.
With Lean Six Sigma and DFMA, product development will:
- simplify a wide variety of other manufacturing steps
- reduce assembly time
- have potentially fewer suppliers
- reduce production floor space requirements
- enable a first pass part count reduction as high as 50%
Reduced, fewer steps could mean bigger savings. So Lean Six Sigma can be good to your product development, too. 
Six Sigma : Your Resource for Strategic Management. Meikah Delid. Eversun Software 2006.