I personally prefer the type 1 and now you mentioned thats its more square, i can see the difference.
I don't currently have spats but i would prefer them to extentions because i think then the diffuser looks like it fit with the car rather than just a blatant add on.
I can't see the difference in the two types of extentions. One seems longer thats about all i can see.
I'm going to order one this weekend and I will keep you updated to how its fits etc, but I'm not going for CF.