It is not recommended that you equip your frame with a longer travel suspension fork than the original, OEM travel spec.
Doing so, may impact the integrity of the frame, and void your warranty. Further, modifying rear travel (on FS bikes) is not recommended whatsoever. Modifying the amount of rear travel will affect component clearances which could result in frame collisions. Not only will this affect the geometry and ride characteristics but will also affect the safety of the rider. Warranty considerations will be void in this scenario..