Audi A4 B5 1.8 Gasoline+LPG: Choosing Engine Oil, LIQUI MOLY Synthoil 5W40, Knecht Filter, 300K KM

Hello, I am approaching the oil change and I wonder what oil to pour into the Audi A4 b5 1.8 gasoline + LPG (founded about 150,000 -Km) 2000the course of 300,000 has so far been poured 10w40 mobil I am thinking of changing to
LIQUI MOLY SYNTHOIL HIGH TECH 5W40 oil
knecht oil filter
and make him a motor lotion about this LIQUI MOLY ENGINE FLUSH PRO-LINE ROSE

tell me if it's a good choice or maybe something else, put in an old-school car and drive a little because it wants to refresh it a bit

The rinsing will not hurt, the viscosity of the oil does not change.

In general, the transition from 10w40 to 5w40 is in my opinion not harmful. It's a myth that it hurts. For example, in a previous work in the Mercedes Sprinter W906 at 350,000 km after the purchase of this car, the mechanics dealing only with the Mercedes have passed us in this car from 10W40 to 5W30. No problems, the car did not take oil, etc. I did a similar maneuver in A3 and nothing happened.
As for the oil issue, think if you are drinking 10w40 5w40 will be more saws. Regarding the oil, buy Valvoline MaxLife 5w40. That is, after 15 thousand km the oil does not turn black, it becomes dark red. The car is more quietly operating than eg on mobil or motul, the car uses less oil. Read reviews about him. I'm just flooding myself. What about the filter, why do you need more expensive Knecht? whether you buy Filtron or MAN or Knecht will not feel the difference, it's just a filter. You pay for the brand only. For example, the motor filter for the A4 B6 I bought Mana, Filtron and Hart and it was the same because it was just a filter. So why overpay.
As for the fact that it is age ... generally reportedly the synthetics are healthier for the engine. So how is he going to get him out of health? Why not? But if you drink oil sparingly, do not change it because it will be worse.

Thanks for a quick response, so I will be at 10w40 I poured a mobil, I will try to pour VALVOLINE MaxLife with the same density 10W40 and I will ask for better mobil or valvoline so far I have been pouring all the time mobil.

Hey, what did you do not invent. If you do not sweat it is ok. Ew. gaskets as something appears, assume new company names such as Erling immediately.

I poured a motul and after a while the yellow indicator light with the MIN sign lit up for me and the oil level is OK on the dipstick, what could be the reason?