Depends on your view and circumstances
Do you intend to keep it long term ( i.e. 5-10 years or more) or do you want it for 1-2 years then shift it on?
Are you a perfectionist with the condition of your cars? Can you live with minor mechanical defects or would you need to get them fixed pronto or it would continually bother you until you get it sorted?
I only ask as if you can live with it then you will be fine but if you want a sorted car then you will find yourself opening your wallet far too much on a potential purchase like this.
Even the little bits like a new set of badges and sorting a few interior blemishes soon adds up on top of servicing. On a bad year these cars can cost in excess of £5k maintain/repair/service
I am not trying to put you off I am only speaking from my own experience... In 5 years including modifications I have spent nearly the purchase value on my "rough around the edges" manual 4200 GT which isn't far off the price of that Grantusimo you are considering and the project will continue
I am keeping my car long term - it has been fun but it is an expensive hobby if you start with a tired car