Well do u even have to ask? 540i all the way (but my opinion is hella baised lol). Only thing with the 540 is your wife may have a faster car than yours. It should also depend on what ur wife wants since she will be driving it. I personally hate toyotas and will never own one.
PS. If u need help getting rid of the windstar in the funest way possible lemme know and ill come up and give u a hand......lol