locking diff questions

I have a 97 tj and I am thinking of putting a locking diff into it .I am not sure which is the best i would like to keep it a daily driver. So far i have put 31 cooper discovery stt on it.And a afe cold air intake, jet proformance chip and 2inch body lift.Along with removing all carpet and rhino line the the floorboards and the complete underside of it.Also put kewood head unit with infinty speakers and sound bar xm, and some other small goodies.I love to take it off road and go two or three times a month it stays muddy and am always looking for challanges for it.Any ideas would be alsome thanks.