If money is the issue, go driveline. Bill and Lane are stellar fellas and will set you up right and help you sort out any issues you may encounter.
When buying from EBay, make sure they are reputable sellers with an actual shop. Some of our sponsors do sell on EBay so it might make some sense to call a few direct. Many of the people selling the stuff in your photo are just drop shipping and making their cut, and will not be able to weld your crank, port cylinders, make domes, or help you sort out issues. Remember saving $100 bucks can mean the difference between a runner and a dawg.