Looking at the kit above and the other SC Vortech both are gear driven SC.
I wont comment how good or weak they are other than to say that they both have unusal shapes.
But the thing that stands out i guess being an affordable pair of kits is there really isnt any real customization of these blowers and by using the standard item really doesnt blend in. Something im not a fan of.
The first one with the spaghetti pipes and the second with the SC back to front.
I guess that they can be reversed rather than the normal clock wise direction .
What i would prefer is to shape the actual rear of the inlet and the outlet.
Something that i have done on my SW20 and something like this.
The time and labor is making the moulds but i have done that before. Then get them cast. Thats easy as i have a foundary close by and really cheap.