XC90 Purchase decision V8 vs. 3.2

Maybe someone has interesting information for me, which makes it easier for me to make the decision: I have 2 offers that come into question for me: – V8 Executive, 02/05, 80.000km for 39.900 – 3.2 Sport, 12/06, 18,000km for 56.900 incl. Navi, GSM, standing heating, sunroof,… the prices are from the Austrian market (nova, etc.), therefore slightly higher than in Germany. nevertheless I do not understand the big difference between V8 and 3.2 completely. since I have to grip almost to the V8, because the favorable price compensates the higher maintenance costs by far. or do I look at what? what does it look like with the expected maintenance costs for the V8 in the next 4 years? I drive about 15,000km/year. are there rough repairs between 80,000 and 140,000km to expect? someone has experience with the difference in realistic petrol consumption between V8 and 3.2? I mostly drive in the rural small town area and around the big city – rather little thanks for your help.