sagging rear ended 98 altima

[supadave81]

hey guys
i do have a question about shocks an struts for my gle 98 altima
i am compete in car audio competitions an my sound systems are usually pretty heavy an are now causing my car to sag in the rear, an i was wanting to know what kind of shock set you guys would reccomend for me. i won't be putting it on the track or anything but its a daily driver so i dont' won't something that will make it look mean on some rims an wider tires.
i was told by a good friend to go with a lowering kit with stiffer springs in the rear to comphensate for the weight.
but i am asking you guys cause why ........................you are all atima owners tdhanks in advance guys look forward to hearing from you.