Welcome to the forum.
Any pictures of the pipe you're trying to install? A new mid pipe is probably worth the extra few dollars on such a nice bike.
From what I remember your bike has the separate headers/mid pipe configuration, this changed on the later models, meaning you would require headers and mid pipe.
Early 750's had "twin" mid pipes, but I think be 02 that was pretty much history.
This means that the 750 mid pipe should fit on the Senna 1000.
I assume there is no Lambda sensor on your catalyc converter?
I'm sure you'll be just fine. Remember to undo all the bolts which hold the system together when installing the new part. You need to be able to "wiggle" everything into place and line everything up before tightening.