IMS failure - how can I confirm my engine is toast?

[Townhome]

I just bought a 2005 Boxster S within IMS failure confirmed by the Porsche dealer. The seller said it still runs but not to start it as the oil has been drained and the oil filter removed by the dealer.
Is there an easy way to check to see if the engine is non-salvageable. Could I do a compression test to confirm? Do I need to pull the transmission to check the cams are still in phase? Does and IMS failure ruin all engines? Is there a possibility I can remove the transmission and clutch assembly and simply replace the bearing with an upgraded IMS bearing along with a new RM seal, a new clutch of course, simply flush the engine of any potential foreign particles and be up and running?
Thanks for the advice.