Opel Vivaro Purchase Advice

Hello guys, we might want to get an Opel Vivaro. Who can give me tips about the best engineization and the durability of the technology? I am most interested in the 2.5 CDTI with 135 or 146 hp, because I drive approx. 25000 km a year and 80 percent highway and then only a diesel would be possible. I have read a slightly older Vivaro brochure, there are almost endless variations, but I think that for us the double cabin is more suitable, since one lagged r the 2nd row of seats has enough cargo space (we have 2 big Leonberger dogs) and this can also allow as a truck. How is it with the insurance and the tax? Is a truck registration (about 180 € tax per year, compared to approx. 420 € as a car) useful and how expensive is the insurance with both variants? About your posts I am already looking forward. Greeting Peter