Do you have steering wheel controls? Does the car have theft lock enabled? IIRC you can get and adapter for the hands free, and theft lock is a pain.
Following advice is for the base sound system.
Buy harness/antenna adapters, the dash adapter plate and its not bad. Honestly its more tedious to tear down the dash than remove/install the head unit. Biggest issue will be theft lock, if a code has been set and you don't know it, you can Google theft lock, there is a procedure to get a code from the radio and a phone number to call to get the unlock code.
I wholeheartedly recommend Alpine head units, I had the Mech-less Bluetooth unit in my 99 worked amazingly. Though if you are updating your head unit speakers should be short listed as the OEM ones are really bad.
