I thought the stopper might have blocked some flow because you tested the 6025 with standard mod to be 1,111gph, and with wide flow and the stopper to be 1,078gph. Now to think of it they are so close they are within the margin of error under this test.
While the stopper worked perfectly for its intent, it still has the normal startup clicking noise when corrective action is needed. If put on a rapid wavemaker that can be an issue. I don't know if you noticed that. I am hoping to find a way to reduce that noise.
One thing seems clear, both 6025 and 6045 probably have the same drive unit/motor since they both draw 7W, regardless what kind of flow they produce. The added drag or lack of it did not make much difference.
Let's do a quick recap:
We so far have done the following on our beloved 6025s: the basic mod (TBM), the wide flow mod (WFM), the full blast mod (FBM), the stopper mod (TSM), and I'd like to add one last bonus, the auto clean mode (ACM).
Compared to the Tunze advertised specs, TBM has increased the 6025's flow by 68%, FBM by 86%. As put by one of the American Idol's contestants: "not too shabby"
BTW I am not an AI fan but the rest of the family are. I can only hope this thing come to an end one day.