Hi guys, been a member on here for quite a long time. Been out of the game for a bit so haven't been on here lately. I need some advice if anyone could help me I would really appreciate it.

Problem-

Audi a4 2009 b8, never had any issues with the car, ownEed it for almost 2 years now. One day my wife was driving, came to a red light, the car started sputtering and loss power. She pulled over immediately and called me so I towed it home. Ran the CEL, codes came up for crank positioning sensor, misfire in all 4 cyl, etc. I turn the car to ac mode, check the mmi for oil level, which was good. Bought new crank positioning sensor, car did nothing. Checked everything. Come to find out, the chain tensioner failed and locked the motor. Fml. No signs of it going bad at all. . No ticking, knocking, rpm idling probs, nothing. Question is... would it be least expensive for me to replace the motor or rebuild the head Bc pretty sure the block is fine. If anyone know of a shop that can work on audi please let me know. Also if anyone knows of somewhere who carries these motor used for cheap, that would be wonderful. Preferably local if can. I'm located in lawrenceville, ga. Thanks everyone