Hey man, you did the right thing. You saved your wifes back and on a road trip, you will be happy with the ride and the room, as will the kids. As you said, you can always pick up another German car down the road.
By the way, did you get the DVD option? For long road trips, I highly recommend it. And your sealant plan is the perfect option.
Last point, went to a Pre-Indy 500 race party last year, lots of celebs, valet parking, the whole thing. We took some friends who were in town and drove our Odyssey. Pulled in and saw Jags, Bentleys, Merc, Lexus, etc. Valet parked us, we went in and met a bunch of ESPN people by the bar, and spent the evening talking sports. When we left, my wife had lost our Valet ticket. The Valet told us we would have to wait while they went out and looked. I told him, "I will bet you all the money in my pocket, and max out a credit card, that I have the only minivan here." He said<"OH, YOU drive the minivan." Two minutes later, my van pulled up. The Valet said, Hey that's pretty nice." Some one yelled out, "Hey, nice van." My wife replied, "Yeah and we can watch Sponge Bob on the way home!"
Trust me, the van works out.