i don't know, for some reason when i compare my crotch with that of bio guys the 5 inch gv looks realistic on me whereas the smaller packers make me look like Ken. I'm thinking it might be an anatomy thing rather than a size question (maybe male parts hang there a lot different from packers), but i'm still trying to put my finger on it. When people wear their packers with an actual harness though, they seem to get bigger bulges.
I can actually kinda see what the idea behind the like real stp thing was, but it was just not carried out well at all. the problem that arises is that you need to glue the rim of your funnel to your body somehow. so that's why they put so much surface there...the peacock funnel system looks really nice, but there is no way you could glue a funnel like that to your body, there's just not enough surface. There used to be a prosthetic (was it the Tyron2?) that was held in place by a string attached to a pad that you have to glue between your....cheeks... but i can't say i fancy that idea. to be honest, it might make sense to wait for the tyron 3 to come out, then let some info leak to reelmagic, since they're cheaper. the tyron 3 is said to come with an stp and a mechanism where you squeeze the balls to inflate the shaft and create an erection.