Hi Kuben
Which Porsche dealership is this? It's not Porsche Centre Chester at Cheshire Oaks is it? They always give VWs as loan cars because the guy who owns the dealership also owns Corkhills VW in Liverppol.
I know other OPCs in the UK have Porsche loan cars.
I'm not sure, but I would say contact PCGB and tell them your concerns about potential loss of value due to the engine change. They are ususally very helpful - I certainly had a lot of help when I was sorting my dual-mass-flywheel problems.
The e-mail address is
customer.assistance@porsche.co.uk
Cheers
Paul