Is it an S-model (turbo, has hood scoop)? If so, you'll want to check the oil level, as these engines tend to consume oil, especially as they age. (My spouse's 2014 Countryman S, about 60,000mi, consumes about a liter of oil every couple thousand miles. I keep it topped up.)

Listen to the engine start up from cold. (Not pre-warmed.) If you hear any rattling or clattering, then the timing chain is loose and you should either pass on the car, or negotiate a really aggressive price cut and be prepared for some expensive and/or time-consuming engine work. But the good news is that even if it has an N18 engine, this is a fairly rare occurrence compared to its predecessor (N14, used 2007–2010).

Aside from that, check the serpentine belt for cracks, expect the water pump may need replacement at some point, and you'll want new spark plugs and engine air filter at your 60k service.

 

My 06 MCS has already had:
New Thermostat, New water pump, Harmonic balancer, Belt tensioner, Supercharger oil change, Front motor mount, and the service mileage in the speedo won't reset.
Plus normal things: Lightweight Enkei PF01 17" wheels, Brake pads and rotors, Automatic tranny fluid, Low speed fan resistor change, Coolant changes, Plugs and wires, Air filters and cabin filters,
- LED bulbs interior and some exterior, HID bulbs, Tyres as I don't drive that much with only 46,500 miles. Oil and Filter changes, Premium fuel now at $4.75 but it's still a fun car.

I still love driving my Mini S, but if I get a big repair to do, it may get traded in for a less fun car and I don't really want to have to do it.

 

Looks great @MiniKar ! Do you do the wrenching yourself, or have MINI/someone else do it?

I do all my own wrench-turning and can't imagine how much I've saved over having the dealer/some other shop do the work. Did a head gasket, S/C service, all new o-rings around the typically leaky block-sensor holes, new struts all around, rear suspension complete rebuild, new brakes. Saved a bundle. Great way to keep repair costs down (even major ones like a head gasket).

 

I do the easy normal repairs at home but the bigger stuff goes to my independent shop 2 hours away. They are reasonable and do very good work.

 

I was thinking the same thing my brother got a bug had no money to fix and asked the shop teacher If he could come after school he would clean the shop and put tools away in exchange store his car and work on it there and use his tools and stuff. The car had 167000 miles when he bought it was 1963 VW ugly green oval window on back. Thank you for reminding me of this and I am going to buy me my Mini. I bought a 2014 Ford and that SUV only had 52000 miles on it thought I scored and heck no I was coming down the mountain from our new Year's family trip and was on a turn and the car shut off. restart the car while in a turn and no steering control spent 4 months without vehicle paid my payments and put out $1800 on top of renewing the tags and rental fees because the shop could not recreate it the problem they had it sent to 2 dealers and 4 shops later. So I am scared to by a used car now. But I really want a Mini and I am gonna get it.