A Omage purchase decision and on e2 conversions, expensive?

Hi, I’d like to join the Opel community and before that I’d rather look for the advice of people who know about the beasts. I just need a huge station wagon to load and drive quickly. I wanted to buy a Passat 35i first but I like the Omega A caravan much better from the size. The 2.0 8V engine I think is a little too weak on the chest, so my eye fell on the 2.6 or even 3.0s Now I’ve read that the most part al This is why I would like to convert it to Euro two or even three if three is possible at all. But two should already halve the taxes. What would I need to upgrade the one??? Bzw, what do the parts cost me at the cheapest place? Installation I do everything myself. What should one pay attention to when buying an A Omegas? Wanted to spend a maximum of 600-700 on the vehicle, I am myself a screwdriver, who has an ode r other little story I can fix myself. Greetings and thank you for your answers, Robert