This has got me seriously thinking-should i sell or keep the E53 X5 ???

[AW8]

Warranty can offer some peace of mind but there can be limitations. The BMW mondial warranty won't cover cars over 100k & a new policy taken out on a car over 60k won't be a cheap product. Other policies exist but most will have all or some of the following.... exclusions, diagnostic costs claim waiver,  betterment contributions, significant excess costs per claim & max claim amounts that won't cover larger bills.

Not saying a warranty is a bad idea but they often tend to be more use for folk with cars under 100k & 10 years old...generally cars newer than the E53.

[Insight G40]

I've had my 56 reg 3.0D for two years now. hit the 100k mark yesterday, having done about 12K since I bought it.

I walk to work, and my wife looks after the 3 young kids, so it only does local miles, so doesn't get as many non local miles as it really needs.

Only thing I've had to replace is the battery, which was partly down to the short trips and the cheap underwhelming battery fitted. Oh and the rear wiper arm, which could have been repaired by greasing up the spring on the old one, but I wanted the sleeker look of the E70 arm.

I am going to have to replace the glow plugs and controller, but they've done 100k so not unexpected.

I din't intend to buy an X5 the day I nought mine, I was just looking, but knew about 5 minutes after I first saw it that I was going to buy it. Everything worked, full main dealer history was complete and it was clear it was a decent example.
I  had looked at two others prior, that same day including a test drive of the first one, and it was appalling.

These are high end cars, with a lot of complicated electronics, obviously not including the tape deck in a 2006 luxury SUV ), and given that E53's are at least 10 years old now, there is plenty of scope for expensive repair bills.

However there are still decent examples to be found, and if you get a good one, you'll have an amazing car.

Helped my parents move some  heavy stuff from the house they've just sold in Surrey to their new place in Dorset, with a heavily laden trailer yesterday, and my dad, who drives an E70 40D was impressed with how well a 10 year old car felt, commenting "It really doesn't feel like a 10 year old car"

My opinion is maintenance is key ,service as specified, use quality parts, and get any issued fixed as soon as they materialise and you'll be fine.
At the same time, you have to be prepared for replacement of parts that suffer from 'wear and tear' on vehicles with 100k such as rear suspension bushes etc.