they come in diffent lengths. im guessing you'd just measure the distance between your bolt holes locked up and layed out. then find a shock that is a little less than layed out and more than lifted so you don't over extend your shocks or anything like that. anyone feel free to correct me if im wrong.
i have junky ones on my truck but they are puttin new ones on at da drop shop
shock placement helps but vw shocks are the best to use i use them on everything from minis to fullsizes, shock placement has about half to do with ride. the other half is the shock
i have mine mounted straightup and down, but the tops are anglrd back alittle. if that helps any.