All previous posts are on the money. I sail on a boat that PO switched from standard fin keel to shallower draft with a bulb added. I'm convinced it was done on a restricted budget with little or no consultation with the designer/builder. It was also designed for centerboard construction. I've sailed the same model with the standard fin too.
Up side - you get shallower draft - but no matter where you go, you are bound to touch bottom sooner or later
Down side - reduced pointing, compromised steering in heavy wind, a one-off boat with diminished resale value. We've priced out a keel swap -
$10,000 (or more)
IMHO - find the boat with the draft you want. Go sailing.