These questions weren't really from a speed perspective so much....

I only asked because the phenom looks just as big as a whip.. I didn't think there would be much difference in thickness ..but wanted to see if they did anything different in that regard

yes your right a cowled engine will definitley be faster than one with all that engine just hanging out in the breeze.. thats why I cowled my diamond dust and will probably do the same to the whip

and as for the weight..I was a bit dissapointed with how heavy my whip is compared to my diamond dust
(bare frames ..less engine and equipment)