You will need to unistall SH4, then re-install in a directory different than the (x86) directory. Most of have it in its own folder or one such as "games." Then go ahead and start with adding v1.5, then JSGME, then the mods.
Welcome aboard to a great site.

We:re always happy to share our vast wealth of knowledge whether it's reliable or not.
Now go polish the props.