What input can I get to clarify requirements for modification by installing later version of OEM parts? I am fully aware of 337 and STC issues, but here is an example of what I am asking. Assume during rebuild of an early model 185 it is decided to install a later models wings. Since the wings are listed in the IPC as applicable to a later model, does a log book entry or field 337 suffice? I have seen many instances with smaller parts/options being handled with just a log book entry. Since this is a major alteration I would think a 337. Any comments on a one time STC being overkill?