shocks for 1995 Buick RM Estate wagon

I am searching for shocks online and now wonder if I need to replace all four when just one is leaking air?And if the front shocks will be the same as the rear shocks?KYB seems to be a brand that comes up a lot in online searches,but I have read here the monroe ma819 made someone a happy choice.I will not be installing them myself.I have already read where it is a tough job.Any advice on what major car repair place, not to take it to?