I'm doing a A-4 to beta 16. There's a lot to it. I replaced the fuel tank and lines, exhaust arrangement and water lift, electrical, stringers the engine rests on, sound proofing, different prop. Some of this is necessary like higher stringers and prop, some because the old items are at end of life like the steel fuel tank, and some because while the engine is out it's relatively easy, like sound proofing. A question is how long are you going to keep the boat? You won't get the money back from diesel replacement. A moyer rebuild will be lots cheaper but how long is he going to be around to provide that A4 support? while not yet done I found that given enog time and some re-work I can do as lot by myself and bring in the professional at the later stages. like drop-in and alignment.