Hi
Lovely cars I like the BMW's I have a 523i at the moment.
Just be aware if the car your thinking of buying is a 3.5 litre engine and automatic its going to be heavy on petrol especially on short runs. You will get more to the gallon on longer journeys.
A 2002 is going to be expensive enough to buy so shop around. Have you had a look at them on carzone.ie it will give you an idea of the going prices
a 5yr old 7 series has already had some serious depreciation. They are probably the most heavy depreciators over the first year according to a mate of mine in the trade. The old man has always been a BMW driver and most of the time they have been very reliable. Lovely to drive too.