[EC900]

I agree with others, not enough info being given to get a forum diagnosis. You say you drove it in and they say it’s a no start/get started and now it shifts terrible for them. Hmmmm.

But definitely get another garage opinion, pay the service fee and flatbed if you have to just out of that ‘reputable shop” that seems to want to rebuild-as-they-go. Could be they don’t want any warranty issues so they’ll replace everything they deem questionable.
They may be reputable and qualified but maybe they’re are used to no-quibble big spenders. Garage bays look like a spa? Lots of clean classic cars inside?
If you paid up and they gave your a detailed inspection report, shop around for estimates and options.
Shopping will add up in estimate and inspection fees too….like a PPI that could be at 1hr of shop rate.