2010 VW GTI rough idle

I am posting this for my husband because his work restricts him from it, so I will do the absolute best that I can!

HELP!!

His car: 2010 VW GTI bought/sold in America, less than 100k miles (~92k), manual transmission, 4 cylinder. He bought it CPO when it was less than 1 yr old, did almost all maintenance at the dealership, always on schedule. Been a commuter car, never really driven hard, never taken on road trips or anything major. No accidents. Car never had major issues until we wanted to sell it…

It started having a rough idle & check engine light, so we did the basics first: oil change (at a shop we know/trust for years), new spark plugs, new cam shaft/crank shaft sensors (thats what showed on the scan tool for the check engine light).

None of that changed the rough idle or the check engine light. One shop told us the timing chain skipped some teeth and needs a new tensioner. Another shop just said there’s metal shaving in the oil pan and it needs a whole new engine.

** We already bought the replacement for this car!!! This car just needs to get sold!! We are not spending tons of money rebuilding anything. If it’s major, it’s getting scrapped/donated**

I explained that to the shop and they said they would do a “compression test” of the motor to see if they can pinpoint where the issue is.

Is there a way to diagnose this without taking the entire engine apart? If we are trying to sell it as is, and the car (in good working order) is worth roughly $8k-$10k, what sort of price drop would be reasonable? Are we getting hosed by so many shops??

Thanks!!