No problem Martin, I was 29 years in vehicle development so can find my way round 😉. Yes, the car will be tight at first in almost every moving part. It will also do some learning based on your driving and it is programmed to be suppressed while the engine beds in. When these things change depends on the mileage and the way it’s driven but usually by a couple of thousand the tightness will have gone and by about four or five thousand the mapping will have relaxed and it will feel a different car. As for the engine noise, the big risk in getting optimum performance from it is to advance the timing so as to get the fuel to start pushing on the downward piston right from the top of the stroke. Think of it like pedals on a bike, if you only start pushing part way down it isn’t as effective as right from the top. They do this by timing the spark far enough in advance for the expanding gas to reach full pressure near the top. The problem is that if they do it too early the fuel will flash rather than expand and you get a knock which is sometimes described as pinking (really called detonation). There are sensors that hold the timing of the spark back but it reduces the effectiveness as described. Now what a lot of people don’t realise is that high octane fuel is less volatile than low. It doesn’t go bang like an explosion it burns in a very predictable and consistent manner so by using high grade fuel, it not only keeps the fuel system clean, it allows the timing to be advanced without knock and it really smooths out the engine to sound better. You rarely get enough improvement to cover the extra cost but in my mind I prefer the sound especially in a Lexus and I’m happy that the fuel system gets some protection as the fuel is dosed with detergents.