Most of my cars fit this criteria and for the last decade plus, this has not been an issue.

 

Step back and think about the average high end Merc or Audi buyer versus the average Japanese buyer - including Lexus to a slightly more limited extent. Many American German car owners keep the cars for 1-5 years then get a new one. Much of the prestige and appeal of owning a Merc, for instance, does not* apply to owning an 8 or 10 year old one. Few are impressed by a 2007 5 series.

German automakers need to engineer cars to sell at high prices when new - overall long term reliability is simply not a top priority from a sales/income perspective. They are willing to incorporate complex, unproven technology to get S class Mercs off the show room floor at $150k. To buyers of a new Mazda (or Honda, Toyota, et cetera), however, that is unacceptable.

These cars are not designed to acheive the same objectives and unsurprisingly they do not.

 

One of the most problematic cars I've owned was an E46 M3 (owned for 2 months). Had a broken door lock actuator when I bought it, and cooling issues when I drove it to California (~300 miles) in 100 degree weather. This was a 2003 with 63k miles, so not overly used and had good service records, one of which was a rod bearing recall at 17k miles. Problem was the viscous fan clutch slipping at higher rpms, causing the fan speed to drop. I had to drive as slow as a semi-trailer with the AC off for 150+ miles until ambient temperature was cool enough.

But even after all of that, I'm looking to buy another BMW for a daily driver. Why? Because it's a joy to drive.

Also, straight-6 vs a V6 in terms of smoothness, the straight-6 will always win due to inherent balance. The VQ35 is better balanced at higher rpms than a VQ37, but they're not close to the S54. The VQ37 especially is very coarce at higher rpms.

 

I'm looking at 996s right now. I don't think the failures are overblown. ~5-10% failure rate resulting in total engine destruction. Not good... You are more than likely not going to have a problem, but on the 1/10 to 1/20 chance you do, it's going to cost you BIG time.

 

That is exactly why I didn't go Porsche. I understood and appreciated that the failures were rare-ish, but if it goes bad, you'll need to pick a body part to donate to science.

 

Which would be fine if those cars actually delivered some marginal advancement, even if it is insignificant, but Mercs and BMWs really don't, and often times they are behind the curve. Hybrid tech, self parking, radar cruise control, etc, all items that they did not invent/patent/pioneer (correct me if I'm wrong). Heck, I get range rovers, for all their shortcomings, few cars offer the luxury in an off road capable truck and they are arguably the benchmark from the factory. It's measurable and discernible. And imo they have the best designed (styling) SUVs. I don't think anyone would call an S Class beautiful, especially the last gen. The german makes love to talk about how they have this or that, but no one asks the simple question well how is that better than the existing tech from say Toyota? Why does your rear bumper need all those extra covers and trim pieces, what technological achievement or benefit does the consumer enjoy? Or is it simply there so that in an event of a common rear end impact Merc can ring up the register more.
I hate this kind of business starts a trend that other manufacturers adopt.
The VW Phaeton proves that the populace don't buy based on merit, they buy based on name.
Those makes are able to be the best in their markets because the cost to crack that market is too vast because those consumers will blindly trust their brand, namely they're label whoring. If Cadillac truly made an S class beater and charged a price that reflects the fact that it's better than an S class, no one will buy it because they want that propeller on the hood. Lexus essentially has to sell the IS at a cheaper price than a comparably equipped 3 series despite it being more reliable, better made, and enjoys better long term cost of ownership because a few mags say it's more fun to drive.

 

The guy that bought my BMW made a good point. Don't buy a BMW with 60k miles, buy it at 100k miles. The guy that owned it from 60-100k already took care of the big ticket repairs like water pump and axles.

 

My daily is a 2004 VW Jetta 1.8T. Bought it new from the dealership, it's reaching 120,000 miles and still going strong. I think the key is to have good maintenance from the begining.

 

Not a personal comment at all since I see you are in the US, but I'll use this as an example. In Europe, I think this is where most buyer's expectations for a car's reliability are. If it goes 100,000 miles without needing to be junked, it is "reliable." That's because most people just don't drive very much and cars rack up miles very slowly. Also, high cost of ownership (taxes and fuel) mean that all car ownership is skewed towards richer people who can afford new cars more often. You see that in their ridiculously low used-car values.

In the US, 100,000 miles goes by in five years for a lot of commuters, and we measure our road trips in thousands of miles, not hundreds. It's after 200,000 miles that a car's reliability starts to be established. Modern German cars built to European expectations of longevity fail to meet US expectations.

 

Yeah... ok. Because things like sensors, actuators, pumps, hoses, seals, etc don't go bad after 100k.