You'd probably be hard pressed to notice any difference without driving an identically setup car with manual turbos back to back. All of the piping and bolt holes are the same, it's just the taper (A/R ratio) of the turbine housing that's different. If you really wanted to you could try picking up a blown set of manual turbos and swap the exhaust housings so you have the .63 turbine housing, though as mentioned, you probably wouldn't be able to notice the difference anyway.
