babyduke
You are in the same situation as the previous owner of my X5. He put money in it for years, until he had enough. So as with any car when the miles and years go on, you either have to be able to make your own repairs or have the money to pay someone. So if you like the car, keep it. And if you want to sell, call me.

I have no intention of ever selling mine. I think I paid a fair price for a vehicle that I really wanted, will always enjoy owning and enjoy driving very much. In all reality, how far will the money you sell it for go towards a new vehicle? If you don't have the money to keep it up, but love your X, look at it as a project, let it set in the garage and work to keep it in tip-top shape as funds allow, and buy another daily. On the other hand, I believe in having vehicles paid in full, with the exception of business vehicles that make you money. So, ultimately, the decision is yours, according to your individual situation...

I don't DIY but have a reliable mechanic who's taken care of me well for years. But he's not a bimmer specialist and often takes trial and error to figure some things out. Plus if he ever retires which won't be long, I'm screwed. :dunno:

IMO, If you lost trust in the car you should move on.

170k+ on my 04, 3.0 and with proactive maintenance and about $7 thousand since warrantee ran out (doing all work myself), my car has never left me stranded and i still have trust.

what do you think you could get for it in a sale? these are a DIME A DOZEN vehicle so you will get nothing useful. at best you can afford an OLDER used (obviously) honda accord/toyota camry. If you're looking at buying new, then you're back to having a monthly car payment/loan payment.
Choose wisely.

You have done most of the big stuff. If you want you can replace the alternator and voltage regulator now and get that over with. Do your battery if it is 5 years or older.

Same with the fuel filter and fuel pump. Again, at your mileage those things are hit and miss.

If you had a Honda or something as a daily you could do all of this stuff very slowly. Between detailed forums posts and you tube I think anyone can learn to DIY if you have the time. Harbor Freight gets you good tools cheap.

As the original owner I would feel best about doing those things to the car since I know all of its history. Most of us, even with service records, are left in the dark to a degree.

Beating a dead horse
 

I think we all have beaten this topic to death already.

There are lots of choices with vehicle purchases- New Vs Used? Warranty VS None? Own vs Lease? DIY vs $$$ and on and on. Everyonegets to make choices. Most on this forum tend to make SMART choices by DIY to reduce cost of ownership and to improve reliability on 10+ year old performance SAV.
If you plan it right most of these vehicles will go way passed 150,000/15 years and still look good and get remarks that start with "Is that New?"
DIY, learn from the forum = happy owners
Give your repair shop of choice $$$ (Dealer add 40%)when something happens will usually make you great friend of the shop owners, but not much else.

DIY and drive until there is nothing left. That will be ROI.