A newcomer to the A2 owners and a few small questions

Hello people, I now have a daily driving distance of 250km to master by changing my apartment. I did not want to expect my old Mercedes G and it would not be bearable from a financial point of view. Now I have bought an Audi A2 1.4Tdi this weekend. 120Tkm on the speedometer and year of construction 2002. Since the route I travel to 50% highway 45% highway and 5% city, I am thinking about whether I can not have a cruise retrofit. Tempomat retrofitting or should one use the accessories here? e.g. WAECO Has someone already had experience with the installation? How are the costs? if necessary workshop recommendation near Hamburg or Hanover. At the moment have been raised on my A2 175er and for the winter I got 165. Since I not only want to save fuel, but also want to be safe on the road, is there a tyre size that has proven to be ideal for the A2?