From what I recall the Accushadow is designed to be a 2-3" gun at 50 yards. CZ guns are very accurate by default, the bushing just tightens things up a smidge to give you consistent and repeatable bullet impact at ranges most people would use a carbine for. The ammo you choose at those ranges will also play a big part in repeatable points of impact.
The Accushadow will have a small advantage at the ranges you are shooting in those competitions, but it's going to come from the hand fitting of the gun, competition springs and polishing of the trigger, sear, hammer, etc. A Shadow 2 with competition tuning from CZC, CGW, etc will perform just as well except for the very top rank of shooters. By top rank, I mean the guys that have their sponsors build their guns for them. Average to good competitive shooters, myself included, would probably be better off spending the extra money on ammo, gear and range time.
Having said that, I run a Bull Shadow and I am very happy with it. I like the craftsmanship, feel and the knowledge that if there are misses, they are my fault and not the gun. The high priced gun does not make me a better shooter than a tuned CZ 75 that costs about a 3rd as much, but it makes me happy. I don't regret it, even though I know I would have been better off spending the money on ammo and range time with my CZ75, or going with a better belt/mag/holster set up.