With the modern shotgun ammunition of today with cup wads and modern smokeless powder 2 inches on you barrel would not produce measurable differences in your shotgun. The modern shells produce patterns about one choke tighter than what your barrel is choked. The long barrels of yesterday were used because black powder burned skow and they were trying to get all the push they could out of black powder shells before the charge left the barrel. Some folks can't leave go of the notion that a longer barrel is better. One situation where a longer barrel helps is in swinging the shotgun by making the swing smoother and keeping the gun in motion. That is wy trap shooters may use longer barreled guns.