As an owner is it better to a) install mini splits or  b) make renter supply their own air conditioner.

Have both an air conditioner and a dehumidifier system. 

He did a full renovation and in the process switched from a wall heater/central forced air to mini splits.

We've upgraded many places especially when electric heat, heat pumps, central air conditioning is added into the equation.

I'm optimistic that Air Force base upgrades (North) and the Trinity hospital development (South) will create a positive growth trend over the course of the next 5+ years. 

If you get specifically low flow showerheads, the cheap <$10 ones at Home Depot, tenants will complain.They'll just switch them out back to "normal" ones- people like strong showers.There are some that use air pressure to make low flow feel stronger.

He did a full renovation and in the process switched from a wall heater/central forced air unit to mini splits.

But as I indicated the formula seems to be up in the air at this pointSince you are in a different region, I went through 10 or so of the last accepted investor bids in North Carolina and not one of them was accepted with a net below +-87%. 

You could sell and 1031 it into the next property but you'd usually have to time the sale of your existing property and the closing of your new property right.I also wouldn't worry about having central air in the property unless that is essentially a requirement for you to remain competitive with the rest of that market.

If this election is made, the term “section 179 property” will include any qualified real property that is:Qualified improvement property as described in section 168(e)(6) of the Internal Revenue Code, andAny of the following improvements to nonresidential real property placed in service after the date the nonresidential real property was first placed in service.Roofs.Heating, ventilation, and air-conditioning property.Fire protection and alarm systems.Security systems.https://www.irs.gov/publicatio...