I took a look at those. Makes sense to add some support(in their case foam behind the silicone face) as thin silicones are too malliable if the size is off(and thus it may cover up one of the bores, and whatever else it does to the sound). This is the pitfalls of spinfits, and also the stock wide bore tips. Also, the complies can effect the sound due to the material.
I recall Sony EX-1000 hybrid tips they did something similar with foam supporting the structure behind the silicones.
I probably would not have heard them to full potential if it wasn't for tips I got from other iems. The problem with the stock silicone wide bore is like the spinfits, thin and easily malliable, and medium to large is significant size up. There should be a medium-large size in between. Large is too big for me, and medium is too small.
The tips I've been using is similar structure to the Spiral Dots, they seem ideal. The silicones should be thicker to resist bends better.