oil additive

w213 2 litre diesel 2017 .for many years I have been using engine oil addative with great success , last 10 years Active 8 ; Mondeo diesel 449.000 miles ; Audi A6 2 diesel 360,000 miles ; both cars engines still good but other big problems with cars .before this used slick 50 for many years ...

:confused: Merc E Class 2.2 cdi auto saloon 2002, 110k miles. Any experience/benefits of using Oil Flush, Oil Additive and Diesel Additive - for obtaining all the suggested benefits. I am particularly interested in obtaining a good economy - having done everything else (tyre pressures...