If the car has been maintained well so far and does not have any big rust issues in the body or the brake lines, then assuming it will continue to get great maintenance it should be able to get well over 250,000-300,000 miles. I bought my Special almost 15 years ago for $8900US, and looking at my maintenance records so far (including oil changes, multiple sets of tires and brakes, fluid changes, belts, filters, transaxle rebuild, suspension parts, EVERYTHING), I've paid more than sum in maintenance in that time. I love the car of course, so I'm prepared to spend it all over again over the next 15+ years.
At this mileage, things will start to show wear and tear and need replacement. Many parts are best replaced with Mopar parts, which will be difficult to find in Europe. Some of our European members might be able to help there.
So, assuming it has been and will continue to be maintained well and not neglected, it's up to you whether the expense is worthwhile. Engine and transmission failure will be far off. If it was neglected previously, then some things could be suspect. Once you do the tires, you won't need to again until they wear out, and if you use a Gates timing belt kit with a Mopar non-Value line water pump (use the updated part number posted here on the forum!), you won't need to do that again for another 7 years or 104,000 miles. Everything you listed is a wear/scheduled maintenance item and the cost of it should not be held up against the value of the car. That goes for any car.
If you don't know the history of the car, one thing you can do is have the current oil tested by an oil research lab. Here in the US we use a company called Blackstone Labs in Indiana, perhaps Europe has something similar. Collect a sample of the used oil, send it for analysis, and finish your oil change using good quality synthetic 5w30 oil. When you get the report back, it will show you how well the engine is wearing and whether there is an issue. That may help you decide if you want to put more money into the tires and timing belt.
What's helpful to most folks here, is many of us are able to turn the wrenches ourselves and save a boatload of money. To do that same amount of work on my car here in the US, doing it myself, I would be spending under $1500US, perhaps a bit over $1500 ($1600-1700?, been a while since I priced out tires and brakes) for a good full set of Continental tires, full set of good ceramic brake pads and coated rotors, and Gates timing belt with Mopar water pump. We're able to do this in large part with the help of this Club and our Knowledgebase available to members. If you decide to keep the car and take on some of that work yourself, joining the club will be an invaluable tool! I replaced the timing belt on my car this year and paid only for parts, less than $200US (timing belt kit, accessory belts). It's the third time I've done a timing belt by myself.
2002 Chrysler 300M Special - Deep Sapphire Blue/Storm Gray Metallic - 142,000 miles