Recently purchased a B8 RS4, and now it's in Audi having the engine removed

Story goes, I bought the car on the 10th of last month, it was a used one owner car with a clean history and 11k miles on the clock, on the 12th I headed for the LeMans 24h, car never missed a beat all the way there, however the day of my return about 70 mile from Calais the management light flashed up and the car started running lumpy, fortunately we had Vagcom with us so scanned the car and came up with multiple misfires. My thoughts were oh great coil packs however having got recovered and the car being delivered to my local Audi dealer. They proceeded to in estivate only to find the coil packs weren't at fault and it was something much more sinister which they were trying to find out. A few days later I recieve a call to say they have found one of the exhaust valve springs has failed/snapped

That's as far as they are at the minute I will try and keep this updated with more info as I when I get it.
Any of you guys encountered anything similar ??
Not an ideal first post granted lol.
CheeRS
Chris