Congrats on your MINI!  

Continue the routine maintenance religiously and you can minimize potential problems.

Congratulations and good to know you have a mechanic that will work on it if needed.
And yes, we know that feeling.

Thanks for the advice.  I asked my mechanic and he said he has worked on them before.  I have upgraded to full mini owner.  Drive it 3 hours home and freaking looooove it. I will deal with whatever comes up.  

Did I mention I love it

If it was stock and in as good a condition as suggested, you still would face the shop costs of a BMW/MINI dealership for parts and labour. If any of the many improvements include engine, transmission, suspension or similar upgrades that are not dealer sourced, you'd be facing an uphill battle to get things fixed. A 12 year old car also may be facing parts availability issues. Being at a distance from a dealer compounds the problem.
If it is so good, why is your friend wanting to sell? Is he facing similar maintenance and repair forecasts?

Unless you have the skills, experience, tools and cash to do your own repairs (or a fat bank account), I advise passing on this deal.

Yes to all your questions. BMW MINIs are check book mechanics.

Well, it's going to require more shop time at higher prices than a ford focus on average, but less than a Range Rover.

Does that help?

My friend is selling a 2006 JCW sport with many improvements.  I trust he takes very good care of his vehicles and he says he had owned it for over a year with no problems at all.  I'm new to minis and new to foreign cars.  I also don't live close to a bmw dealer.  I have read a few reviews other places and I'm kinda nervous about it.  My main concern is this going to be an expensive headache.  I know that's a broad question so I'll try to narrow it down.  Is this going to require higher than normal shop time at higher prices?  I'm looking forward to having a little fun in it but don't plan on dogging it out racing.  Is it required to run premium gas?  

I'm not trying to talk myself out of it but don't want to be regretting it if that makes sense.