Flowtech Cuttout
It will be cheaper to do it all at once. But it does not all half to be done at once. But would not suggest getting a flowtech, they are not made of to much quality.
Mine E-cutout hadn't arrived when I had my Flowtech cutout installed, so we guesstimated it, and I ended up losing some ground clearance b/c it was aimed a little lower than I'd have liked. But I ended up getting rid of that setup and moved the E-cutout to the rear of the I-pipe where it blows straight back by using a 3" header collector reducer. 

