N reg
May not be as daft an idea as it first may seem, given the way CASA maintenance regs are going.
Some pros - a "minor" modification under the new regs may now require an Engineering Order and a pile of paperwork/money to accomplish vs a simple logbook entry stating minor modification done followed by details and A&P's signature under N reg.
Also - a whole rash of CASA AD's e.g. mandatory prop overhaul at 10 years vs no such requirement under Part 91 (private ops) if N reg. No 100 hrly required under Part 91, only an annual.
Cons - need to find an A&P with Inspection Authority to do annuals here in Oz.