So the Westborough Baptist Church are True Christians, then?
Your definition would seem to exclude Catholics and Orthodox churches and few others under the umbrella of Protestantism.
Salvation is achieved by having Christ in your heart. Whether you are in a catholic or protestant church matters not. However I believe the Catholic church would try to lead some astray, also some protestant churches. Jesus concern is with each persons heart, not which church and rules you follow. Each person must work out his own salvation with fear and trembling, and be forgiven of sin in Jesus.
And, according to James, faith without works, is dead. I always wondered why Christians focus more on faith than deeds.