I usually don't comment on lift kits (especially with the truck crowd) but, ...since this is a van forum and not trucks, people may not have a cow over my comments on the holy "lift kit".
Putting spacers in your front struts/springs changes the angle of you CV axles. That limits the amount of travel they have left by putting them closer to the tail end of their travel radius and will wear out/fail quicker.
Another simple issue right off the bat is you are raising the center of gravity of the entire vehicle. Why in the world anyone would want to do that with any vehicle, let alone a big metal box that's already over 9' tall is beyond me. All that to fit marginally larger tires for a whopping additional 1/2" of ground clearance when it's all said and done.
If you look at professional off road vehicles, they keep the vehicle as low to the ground as possible and either enlarge the wheel wells to fit large tires, or design the body and entire vehicle around the drivetrain and rubber. Because all the ground clearance comes from the height of the tires, but they want the vehicle itself as low as possible for center of gravity. From a mechanical advantage standpoint, it's just silly to raise the entire vehicle and take your suspension components out of their optimal performance parameters, to gain 1/2" of ground clearance.
But people do it for looks, so they don't care about that.
You can simply get a better quality tire, in stock size, with the appropriate tread design for your most traveled terrain and your van will be just as capable as someone who stuck shims and blocks in their suspension and stuffed slightly larger tires on.
You will also likely have less failures and your van will handle better.
But if you think it looks cool and don't care, then ignore all that.
