If your radiator is not plugged up on the inside and ....the little fins are not peened over on the outside from the blast of small pebbles and.... you do not ride around in 1st gear, the stock radiator should be ok.  A 3 row radiator DOES NOT give you 1/3 (33%)  more cooling over a 2 row radiator like advertised by many of radiator manufactures.  You will be lucky if a 3 row will even give you 15% more cooling.

Make sure your air scoop is present at the bottom of the radiator.  The air scoop is essential regardless what radiator you have.