From reading this it appears there are lots of apparent approaches to the "legalities"
I would like to post a little documented "facts" as I would call them. This is from my:
Experimantal Operating Limitations
Operating Amateur Build Aircraft
Phase 2 document
Operations Outside the Assigned Test Area
The paragraph below is exactly the same wording as in the Phase 1 Document.
Operations in the Assigned Flight Test Area
Paragraph:
(19) After incorporating a major change as described in 14 CFR & 21.93. the aircraft owner is required to reestablish compliance with 14CFR & 91.319(b) and notify the geographically responsible FSDO of the location of the proposed test area. The aircraft owner must obtain concurrence from the FSDO as to the suitability of the test area. If the major change includes installing a different type of engine(reciprocating or turbine) or a change of a fixed-pitch from or to a controllable propeller, the aircraft owner must fill out a revised FAA form 8130-6 to update the aircraft file in the FAA Aircraft Registration Branch. All operations must be conducted under day VFR conditions in a sparsely populated area. The aircraft must remain in flight test for a minimum of 5 hours. The FSDO may require additional time (more than 5 hours) depending on the extent of the modification. Persons nonessential to the flight must not be carried. The aircraft owner must make a detailed logbook and maintenance records entry describing the changes before the test flight. Following satisfactory completion of the required number of flight hours in the flight test area, the pilot must certify in the records that the aircraft has been shown to comply with 14CFR &91.319(b), must be recorded in the aircraft records with the following, or similarly worded statement: "I certify that the prescribed flight test hours have been completed and the aircraft is controllable throughout its normal range of speeds and throughout all maneuvers to be executed, has no hazardous characteristics or design features and is safe for operation. The following aircraft operating data has been demonstrated during the flight testing: Vso_________, Vx_______,
and Vy________, and the weight_______, and CG location _______ at which they were obtained."
Notice all reference to the person performing the modification or submitting data to the FAA is referred to as the "Owner" or the "Pilot". There is no reference to any need for a certificated person to be involved either in the major modification or in the log book entry or in the notification of the FSDO. Also notice that in the occasion of an engine or prop type change the notification is made to the Registration Branch to "update the file".
I am not one to ignore the regs or prudent behavior especially since I had to submit all my records after our "hard landing" destroyed our first Kitfox, but this seems all pretty simple and straightforward. Also keep in mind that this document was presented to me and signed by Richard T Dilbeck, Aviation Safety Inspector, Sacramento FSDO.
With regard to the hard landing. The ultimate enforcer, in my opinion, is your insurance company. My understanding is that if you are in violation of the FARs, your insurance company is likely to say, "Hey, thanks for the premiums all these years, see you later."