Yup - try paying for a good daycare. It's literally as much as a mortgage payment.

When I was shopping for an X5, I drove a 3.0 and 4.4 and ultimately chose the V8 as I just love the pull off the line and passing acceleration.

I also considered a 5-series and the 3.0 felt fantastic in there.

My conclusion is that for a sedan or small SUV like the X3, the 3.0 is great. But for a big, heavy SUV, make mine a V8.

My X5 started smoking shortly after I did the first oil change (I think the previous owner or a dealership may have used a stop leak to cover it up). After the initial sticker shock of repairing it, I decided that I love driving it so much and would like to keep it for a long time that I'll save up and do it.

BTW, there was mention of 18-20mpg. Maybe if the drive is entirely highway at slower speeds like 50mph. I average 15-16mpg driving daily on the highway at 65-70mph with some side-street driving on my commute.

65-70mph in the UK would see you getting 22-25mpg in the 4.4. We have vastly superior quality fuel here. Another reason why we don't see so many of the engine problems as over the pond. To give an example, the minimum RON here is 95, and has been for a long long time.

Oh I didn't realize that. You guys probably don't have the ethanol garbage in your fuel too.

At most 5%, but a lot of the premium fuels claim to have 0%.

Mind saying that, our higher MPG is nothing to be proud of as petrol currently stands at $9.47 a gallon.

I too like the V-8 power and bit the billet and sank money into the engine. I now need a second on for my daughter and no way would I buy a V8.

The OP has a budget...Edogg tell him what the smoke cost you so he gets an idea.

See my first post in this thread. Quoted below for convenience. I have not done the service yet (still gathering quotes from local indy shops) and plan to do the service after the 1st of the year. I'll be sure to post a thread with my experience to share with others.

Telling the OP to not get a V8 because it 'may' have problems is like telling him not to buy a BMW, but get a Honda instead. For £7.5k you could get a very young Kia Sportage. But they are boring, and slow, and bland. For every smile driving wise, you've got to spend a few more pennies. I have a friend who is coming up to his third year of ownership of a 4.8 and he's done 15,000 miles in that time. From 70-85k. He has had zero problems and in fact the only thing he's done to it is change the ball joints and the oil/filter. Mine is at 95k and I've done a bit more suspension work and some pre-emptive stuff. In contrast, I had an Audi A4 that had loads of problems and ended up with a new engine. In opposite contrast I had an A6 that was renowned for camshaft problems, a CVt box that was described as a 'grenade with the pin already pulled out' and yet on that car, in 3 years and 50,000 miles, the only thing I fixed was a CV joint. Gearbox and cams were still totally fine when I traded it in at a whisker below 200,000 miles.

Just got another quote on replacing the valve stem seals to resolve the smoking issue. $2600. I'll be doing it at this shop next month as they're the most reasonable so far.

Also, I'd recommend getting an extended warranty if you can. It probably won't cover the valve stem seals, but it will cover some of the other odds and ends that break.

Risk management
 

Many thanks to all those who took the time to respond. Plenty of food for thought. Buying a used car is always going to be something of a lottery, but I'm trying to manage the risks as best I can. The 'sensible' option would be to purchase a new hatchback but life's too short to be sensible.
I'm aware of the heavy gas/petrol consumption but I don't do many miles so the additional cost over a 'sensible' car is not huge, and is affordable. So, way forward is - look for 4.4i V8 with good service history, have it inspected and may opt for a warranty (c£500 in UK for one year).
Will update when I have bought it!

Always remember, the more miles, the more repairs.
Now who will be doing the repairs?
Are you capable of doing your own?
Or are you financially set to have the repairs done.
An X5 will need repairs.