Is design change and design flaw the same thing?
BRP are hard up on quality, so I can't see them changing suppliers unless there is a major problem that directly affects warranty claims. I have yet to see any signs of problems with the pistons, so I don't see any hint of this happening. So with the same supplier, how would any lower cost translate to a different part number?
I'm with Ken that a part number change was more likely an update. Was it an update to fit both NA and turbo? If the part number is the same for both, then I would guess it was an update. Like DJM said, I haven't heard of a problem with the pistons on the NA engine. Have any of you?
They are not the same IMO. Generally one costs the company a lot of money. The other one generally has an upfront cost in tooling followed by healthy reductions in said component cost.