It depends on what you want to do with the van. If you want to keep it auto you have to be concerned with lag. How do you feel about lag as it is? An s60 would spool about the same.

My opinion is that people can take the basic tII-style turbo a lot farther than they usually do. If the rest of the setup is good enough you can make a little over 300hp at the crank with a tII turbo and if you upgrade the compressor side and port the turbine housing and modify the swingvalve housing etc, you can probably do a bit over 400chp. At that point you are deep into the 12s if not high 11s in a minivan.

So, i would just put an upgraded compressor side on the tII style turbo and keep on trucking. If you never want to make more than low 300s hp i would just stick a 60 trim or a60 compressor wheel in the stock-style turbo and leave it at that. Most people would be better served building a custom swingvalve housing before going any bigger than that on the compressor anyway.