JR, Shortys bolt up just like those awful cast iron manifolds. Other than gaskets, you don't have to change anything. I replaced my manifolds BEFORE any of the bolts broke. An ounce of prevention is worth a pound of cure.
I've read where you pick up a little HP with Shortys; around 20 HP with a CAI, and a tune. But I can't verify that. I could never detect and difference. The big reason I went to Shortys is to never have the hassle of broken bolts.
Everybody can do what they want. But to my ears almost all loud exhausts sound like a four letter S word. I don't want the attention, and I don't need to mark my territory.