SFH - Entire 1st floor is a garage. Convert to living area?

[Anthony Shields]

I cant find much about doing this online since the layout of this house is a bit unusual.
Its a bi-level house. Two story. The first floor is 1500 sq ft, the second floor is 1500 sq feet.

The first floor is entirely garage. Two garage doors in the front, no entrance except the garage doors.
The second floor is a living area and can be entered via exterior stairs. The two floors are not internally connected.

The house is valued at ~600k. The two neighboring houses are great comps. They have similar size lots, both multi story, both are the same total sq ft (3000). The difference is that they have a normal layout. One garage bay, first floor living area, second floor living area. Those houses are valued at about 950k. I assume the reason for the discrepency here is because due the garage space not being counted as living area, the bi-level has to be listed as only being 1500 sq ft.

I'm thinking about converting the first floor into a living area, connecting them with internal stairs, getting rid of the external stairs, and just keeping a single small garage bay. This would effectively double the square footage (from 1500 living area -> ~2700)

This obviously wouldnt be cheap, but if it could add ~350k in value, it would be worth it. I'm wondering if anybody has experience with something like this or if there may be some things I'm not considering. Its different than just converting a regular garage, so I'm hesitating a bit about whether it could actually result in the value improvement that I'm expecting.