There are blurred rules on the data plate. What you have really is with a data plate is best chance to not have the extra phase 1 time and the FAA when you crash can fill that blank out fully. I was told the last one. Once bolted on a homebuilt, it is not certified anymore. It does not mean it can’t be recertified if you sell it. It must be inspected by an A&P and logged it conforms. Remove the tag means it’s yours but still not. If part numbers are on the parts, you are still liable for ADs on them. There are service letters for Lycoming and Continental on how they want you to take the tag off. To them if you don’t means you are not following published protocol and whatever happened is not their fault. The runaround is always about liability. To the FAA it’s about filling in paperwork and to the companies it’s about being sued. You as a consumer have to figure your own best deal.