I replaced the ported barrel in my Performance Center 9L with a KKM.(no can do in CO)
At the distances I use if for (steel challenge, occasional USPSA match) it's plenty accurate, if you can
fit an Apex or have a gunsmith that can do it for you I'd say go for the Apex, if you are looking
for an easy improvement/upgrade and don't need long distance precision, I'd bet it's safe to say the KKM should get you there.