Looking for feedback from........

I was at my last track event at the beginning of this month and coming out of a turn and betting back on the throttle I felt a major vibration. It felt like clutch/flywheel giving up. No lose of oil pressure. I limped it back to pit out, oil light came on briefly but guage was in range. In the paddock I let it sit, checked oil level several times(w/guage in car and with oil stick). Everything looked good and no strange sounds at idle. I wouldn't hear it with the pedal engaged but as I began to release it I would begin to hear it. That's why I thought it was clutch/flywheel. I had a couple guys (Porsche Cert. Machanics)look at it and we all thought the same thing.
Took it to the shop. (Good shop, PCA members, good rep) They did visuals, drove it and gave me an inital diagnosis that the engine needs replacement. (they arrived at this without having gone in the engine.)

I am going to request that they open up the engine to give me a better diagnosis.

Looking for additonal feedback on this. I am not a certified mechanic but I have been around cars/racing for a long time and this one sounds/feels like clutch/flywheel but I am not the expert.

76.5k on engine, went out of extended warranty at 72k. RMS and clutch replaced at 70k.

Sorry for the length of the message.

 

Did they update the release bearing and arm when they did the clutch? There is a TSB on this.