Power Pack A (2280kv 1806) works fine for a 6x3 on 3cell (indicated right on the store page). Obviously going up to 4 cell is something different, however your 6x?, the x (and if more then 2 blades) should matter in this case as they would effect the load on the motor (more load -> more current).
Does the motor in question have a spec sheet/recommended input/prop options?
looking up a random 2306 motor indicates that _it_ can do 3-4 cell at 6in props. looking at another one, also indicates 3-4 cell, but only 5-5.5" props (higher Kv value). So, you definately need to look up your motor specs to see what it is rated for (or look up one as close to yours as possible if it doesn't have a rating sheet).