Well Stuart is correct, the Miramar area is dead and has been for Spring Break. The MIRADOR area, on the other hand is where the action has been historically. Thats the area along Matamoros where Manny's is located. I live here full time, now one block off Matamoros. Safe, yep, as safe or safer than it has ever been. You can find trouble and you already know how to to that wherever you are. You will probabaly notice an increase in military and police activity but that is routine stuff. Increased during Spring Break of course.
The Baja Cantina still does well during spring break. On Matamoros the Ice House and the Ice Box should get some action. There are several smaller places that will open. Pink Cadillac and Barra Vieja will be open. One block off Matamoros a block down and a block over from El Mirador hotel, is Elixer a real hot spot with the local younger crowd, try it !! I'm betting that Manny's will open as well. Yes there has been a shift in Spring Breakers out to Sandy Beach in recent years. Changos and Wrecked come to mind. The old port is always good and has a number of joints that will be active, Sharkbite for one, Boo Bar, Moon Shots and 2 or 3 other joints I don't know the name of. Depending on where I was staying I'd hit the Mirador and the Old Port. Both locales allow you to park the vehicle and bar hop. There will be enough action to fill a weekend. The drive out to Sandy beach is a pain but I think the day activity there might be good on the beach.