The wattage rating of a resistor is an upper value that mustn't be exceeded, no problems using a 25 watt in place of a 14 watt.
Another approach is to use two lower powered resistors in parrallel - two 7 watt 6.6 ohm resistors are equivelent to one 3.3 ohm 14 watt one. As 6.6 is not a preferred value you would have to settle for a 6.8 pair giving 3.4 ohms rather than 3.3. Although this is outside of the +/- 5% tolerance I very much doubt it will give you any problems.
AWEM
Andrew Mawson
East Sussex, UK