So You Basically Have A CVT
Curious as to why you think transmissions like the VW DSG are not an improvement over the 鈥渉ydra-matic鈥?style automatics. They are not smooth. They aren't more efficient (anymore, after hydra-matic improvements). Their only advantage is that they can shift faster in the situation where the shift comes unexpectedly. If the shift is expected (as upshifts usually are), their advantage is minimal. I've driven the VW DSG, it's not smooth. I drove the Ford Focus one, it was terrible. I drove the Porsche 911 one, it's barely tolerable. Would I put up with the tradeoffs if I had to? Maybe. If I were really in a race I'd put up with it if there was no other option. It'd be better on a track than a hydra-matic, but I don't spend most of my time on a track. On a street a hydra-matic or Toyota PSD (power split device) transmission is better.
The auto in the Prius is essentially a conventional auto with some components of the planetary set coupled to an electric motor. I don't know about magic, but it is not at all a conventional auto. It has no clutch or torque converter. Yes, it has planetary gearsets, but it's really the differential gearing (done in an epicyclic) that makes the difference. See, it doesn't have "an electric motor", it has two. And one can act as a generator. And that's the key. Think of it as an input shaft, a differential, then two layshafts, then a differential, then the output shaft. Now that seems pointless, the output shaft goes at the same speed as the input shaft. Okay, now in the middle of one of the layshafts put a CVT (continuously variable transmission). With this, now the output shaft speed goes up (and torque down, or vice-versa) continuously as you vary the ratio of the CVT.
Okay, you say that's pointless too, if I have a CVT just use the CVT. Well that's mostly true, except you can maybe undersize the CVT some since most of the power goes through the other shaft. Okay, now an important step. That second layshaft isn't a layshaft transmitting power, it's a generator, a motor and an electronic device that lets you run the motor at a higher or lower speed than the generator (with a corresponding change in torque levels). Now you have that CVT, only it's electronic. And, as mentioned above, it can be undersized compared to the performance level of the car. So you basically have a CVT, a transmission that never needs to shift. No need for a torque converter or clutch. No need for reverse gear, as you can just program the electronic transmission to reverse the output motor direction. No need for an alternator, you have a generator in the transmission.
And we all know CVTs are great. If you want max efficiency, you can run the ICE (gas engine) at its most efficient speed. If you want max performance you can run it at its most powerful output speed (typically top speed). And that's all before you add in the battery. With the battery now you can remove the starter too. When the car is stopped (output shaft not moving) driving the motor backwards will drive the input shaft forward and crank the ICE over. And you can do it over and over. You can have start-stop (idle stop) with smooth takeaways because you can just use the battery power to get the car up to a few km/h while simultaneously starting the ICE. And if you have juice in the battery you can move the car at slow speeds without starting the ICE. If the battery gets low you can just tap off some power from the generator and instead of sending it to the motor, put it into the battery. And since you have the battery you can now use regenerative braking too to save fuel. It's a CVT without the awful link belt. It's a starter. It's an alternator. It has the functions of a clutch or torque converter without need for those. It allows energy regeneration when slowing down. It does require a fair bit of electronics to do this, but that makes sense for the modern age, like a hydra-matic made sense for 50 years before. It's easily the biggest step forward in transmissions for passenger vehicles since the hydra-matic. A computer-shifted manual just isn't as big a jump, not even close.
There is not a way to remedy bore scoring other than a teardown and rebuild. Bore scoring seems to occur more in the larger 3.8L motors of the S cars than in the base 3.6L engines of the non-S cars. It also seems to occur more in cars that are from colder weather climates. This method also gives you an opportunity to inspect the tip of the spark plugs for any oil deposits or fouling. This will give you a view up into the cylinder bores from the bottom. Since scoring usually starts at the bottom, this is the more complete test as the piston even in it's lowest position can still mask the portion of the cylinder wall where scoring begins. This test also gives you the opportunity to look for any debris in the oil pan. In the cars service history (if you have one) you're looking for oil changes around every 5,000 miles. Due to the hybrid wet/dry sump used in the M96/M97, there have been issues of oil starvation but this is typically linked to cars being tracked in high G force situations.