Porsche's warranty is awesome, they come new with 2 years, which can be renewed up to 10 years/ 200,000kms with an annual inspection & fee, car must be dealer maintained at service intervals in order to remain eligible.
As to buying from Al Nabooda, they wouldn't be top of my list, they are always over priced but cars are normally good (sadly not always though). Given that the Porsche warranty is available to anyone and many owners keep renewing theirs, my advice would be buy in the private market, get it inspected at Nabooda/ Ali & Sons to make sure it is accident free and eligible for the warranty program and use anything that needs to doing to drive the price down with the seller. Then keep the warranty going each year and you will have cost effective Porsche ownership.
Oh and buy the S version, not the base version it is sooooo much better.