Looking to do a flush out since I got this car approx 2 years ago with only 52k miles on it. Do I refill with green prestone or special Sub blue stuff? Any supplemental additives need added?

Green is fine.

For a '96, it probably needs a new upper radiator hose.  Squeeze the hose with your hand, if you hear crunchy sounds it's time for a replacement.

Green if you want no problems. Blue if you want a clogged heater core and more rapid deterioration of cooling system plastics. 

GD

Thank you all ! Funny I did squeeze the upper hose an heard a crunch & thought maybe there's an old rusty spring in there. I think I best change them both & be done with it. Should I go OE Subaru or aftermarket?

OE for easy fitment, aftermarket if you want fitting hassles - having to trim, bends arent quite right, etc...

On 7/5/2023 at 9:34 PM, bork said:

Thank you all ! Funny I did squeeze the upper hose an heard a crunch & thought maybe there's an old rusty spring in there. I think I best change them both & be done with it. Should I go OE Subaru or aftermarket?

The OEM hoses are absolutely notable better quality (stiff/firm/cut different) fit, last longer, and you'll be sure to get the right hose. Not worth saving $10 unless the car is a rust heap nearing it's death. The lower hose and clamps typically contact road debris/chemicals/winter treatments more than the top and are worth checking closely. 

The radiator endtank is plastic, gets brittle and cracks easily, even when leaning over the engine bay and you inadvertently put your weight on it.  The hose is likely fused to the nipple, cut it and peel away if needed.  Also don't go overboard tightening the hose clamp on the radiator end.