Pip'sbeamer

Hi all, I'm a newbie to the site and would like to ask members for advice about my next purchase. I've owned a E36 323i estate since 2001 and loved every minute. However my poor old girl is struggling. Having had a service, a rear wheel bearing, 2 new rear tyres last week; she had to be recovered this week with a suspected differential problem :( If this is the case, I need to consider that it may not be worth the cost of repairing this problem and letting her go to BMW heaven. My problem is...everyone I've spoken to over the years, including sales guys in BMW garages, have all advised against changing her whilst she was fit and healthy. The E36 seems to be the one they all look upon with great fondness. I can't afford a brand new one, but am looking for one between 3-6 yrs old, estate, at least 2.5 litre petrol engine, not too expensive to maintain. I look after my cars, service regularly, maintain well. I would greatly appreciate your informed thoughts, what to steer clear of, what to consider...... Thanks in advance :)