Best source for GM 12580681?

[HappySalesman]

Hunting down a bad miss on cylinder 8 in my LH6. Have done new plugs/wires, swapped coils around and the issue stays. About to do leakdown/compression test, but want to order injectors to get them on their way in case its that. Anyone have a good source? I see ACDelco's listed on ebay but don't want to risk getting a knockoff that makes my issue worse.

[gtstorey]

Looks like GM under the new part 19421333 seems to be the best place. Or swap to something like LS3 injectors with adapter. Stay away from ebay or amazon for injectors.