Just want to insert that the BDR warranty is 1 year and it is a parts warranty. It is the dealer that often assumes the labor as a service to their customers. Some dealers may do this better than others.
Most other brands have no warranty at all.
Powertrains have their own warranties. So if that is your main concern you need to distinguish the differences. These warranties are often non-transferable.
The difference between buying a used kit and a dealer delivered rolling chassis or kit is the dealer should have a much lower margin of error because of repeated assemblies of the same product. It is difficult to declare a particular brand that has a kit offering the best because that will inject a ton of variation into the end product pipeline.
Obviously I represent one end of the argument
