Originally Posted by gatorfast
People are not offering constructive feedback because its common knowledge that warranties do not cover after market parts, especially parts that radically change the car like a supercharger.
Perhaps your local dealer will warrant the work and/or parts but a BMW or other extended warranty will generally never cover non-oem parts.
This. Your SC vendor will likely warranty their equipment (but probably not damage it may cause to other components) and your shop should warranty the labor, but I'm pretty sure that not only will your extended warranty not cover your supercharger, they will deny coverage on any claims that could even POSSIBLY be due to the supercharger.
But OP if you really are intent on hoping against hope here, ask a few vendors for full copies of their policies; they shouldn't have a problem sending you one even before you sign up for coverage. And even if by some miracle there's nothing that excludes it, I fully expect any possible claim attributable to an SC to be denied on the rationale that they're warrantying "an M3", i.e. specifically the parts that that moniker entails, not all of the non-M3 parts you attached to your car and what they might do to parts that are covered.