I have a Shadow 2, fully Cajunized, and an SP-01 Tactical that's fully Cajunized as well. The main differences are the grip, firing pin block, and sight radius.
The sight radius really isn't worth thinking about.
The grip is more of a personal preference but I really enjoy the more aggressive and fatter grip on the Shadow 2. The first time I shot a Shadow 2 it was a very familiar feeling. Almost like picking up a gun I had previously owned. That was the initial thing that sold me on the gun before I bought it. It just feels amazing.
Without the firing pin block on the Shadow 2 you can get a really nice trigger pull. A hand fit disconnector or even the drop-in CGW part makes the Shadow 2 one of the finest guns I've ever owned or shot. My fully Cajunized SP-01 is a totally different feel with longer reset and more take up but still in a class above the rest.
For what you want to do I would say get the Shadow 2 and Cajunize it.