Sorry to butt in here but Dinan stuff does void the actual BMW warranty. The new warranty has the same 4yr/50k mile terms but is provided by Dinan, not BMW. It's a common misconception because of the same terms.
I have a 135i on the way which has the same engine so I've been looking into it a lot.
Beautiful car by the way 
Dinan and BMW coordinate their warranties -- if you have a problem, you can go into any BMW or Dinan shop and get it fixed; you don't worry about who ultimately pays, they work it out between them. And BMW won't try to claim your Dinan engine mods or wheels damaged "their" suspension, drivetrain, yadda, yadda, yadda -- unlike their reaction to anyone else's stuff, other than their own performance parts and Dinan. This is one of the reasons people are willing to pay more for comparable Dinan mode than for other vendors.
