Here's a controversial question for you; can you really take a manufacturer seriously as a marque in it's own right if it doesn't make it's own engines...?
Interesting question. I'm a watch collector as well as a car enthusiast and I buy watches for one of two reasons, rarely both - either design and engineering, or for the quailty of their movements. Sometimes you get both, but it's rare without spending the earth. I think cars are the same, with Pagani falling into the design and engineering category (with a bought in 'movement' and Ferrari these days are all about the quailty of their 'movements' i.e. engines/suspension/brakes. They certainly aren't pretty anymore! Lambo for me fall into the 'both' category, an amazing in-house V12 with an amazingly beautiful body that drives superbly. I will pay a lot of money for the right 'design exercise' piece though, as even though they didn't make the movement, I know it is of great quailty from the manufacture who did.
Adam, cost and value for money is irrelevant for a car like this, they will mostly be owned by Chinese billionaires and driven slowly/parked badly around Shanghai city centre. Us Maser/Fezza/Aston/Alfa owners have to think about what everything costs and whether we can afford to do it, these will just be another hypercar in a collection, rolled out to impress in a game of one-upmanship. Hopefully a few will get into the right hands and we'll see them out and about