Yeah if it's still in warranty. The problem is if you buy it now and sell it later when it's ran out then it's a concern for the new buyer.
How 'cheap' are they anyway?
I certainly would never want to own one without warranty.
I've been having a look at them recently and a decent spec 35i (heated seats, pure white design etc) is about £24k from AUC or about £22k private. Not a bad price at all.