A difference is made through hard work, not prayer.
I am sure if God wants me to come to him, he's quite capable of causing that anyway, and will not wait for a prayer from you. If he has his plan, it seems unlikely he would change that based on your request.
A difference is made both through prayer and works.
" More things are wrought by prayer than this world dreams of"
Perhaps it is in Gods plan that we pray for souls who have yet to acknowledge His existence and His salvation , through the cross. Perhaps it is in His plans that souls are saved through the prayers of the faithful ?
We will ALL find out at some point, how our prayers have effected the reality of events .
I believe strongly the prayers of others have effected my life. I think in time we will know, and the Holy Spirit will reveal the truth to those open to the truth.