While I'm speculating, in a high-demand market like San Diego, I highly doubt real estate prices come down significantly.  

I just try to buy properties where the land value alone is significant or speculatively will be.

People here can speculate and the perspectives are solid but it's actually no way of being sure.

It's hard to speculate what to do with this deal, without knowing more.

They just cancelled the cruise ships again this year and you can speculate as easily as I can about how the oil industry will fare under the new administration or how oil prices will holdup through another year of lower (global) demand.  

People been speculating on that area popping off for decades...I bet a lot of the sales are buyers who are buying into that speculation.

If you are limited to adding the new unit as a JADU, it typically lowers the value of the property as you speculated maybe a little for the reason you specify but more so because JADUs require owner occupancy.  

If you're looking to purchase based on appreciation speculation, venture a little further out, such as Pittsboro.

@Oscar Zendejas I'm down with sticking to the cash flow side of things and not 'bank' on speculation.

Buying on actuals is important otherwise you are speculating.