4 rows are better or better yet crossflow style.

 

3 and 4 row refer to the number of cooling paths in the radiator. A 4 row rad will cool better than a 3 row. For performance, it's really a toss up. if you are drag racing, then a 3 row is what you want (smaller, less fluid = less weight). Since you don't drive hard but for only a little while, you don't need the extra cooling capacity. However, if you are thinking more road racing/autocross, then you would want a 4 row. Since the engine will be revving higher for longer periods, you will want the extra cooling. If it's for a daily driver and you live where the weather is 100 degrees plus for a lot of the year, then you might want a 4 row as well. Although, 3 row will cool just fine for most cars...

 

A 4 row radiator gives better cooling performance when needed. However even on my 81ZXT with the air on idleing in 110+ degree heat the engine never gets hot. If the ENTIRE cooling system is in good shape it should cool down fine unless your putting out major power. There was a looong debate a while back on cooling systems, do a search and you should find it. It has a ton of useful info in it.