you could just add FullSac CVO Power Cores and Screens ..... that was what I finally decided to do and I'm extremely happy (side note ..... I also used FullSac S/S DX pipe w/ 2.25 cores)
yes a tune is widely suggested .....
X2. Went the Fullsac route and love it. Changing out the head pipe will help with heat but will do little to increase the sound. I like the look of the CVO mufflers so did the power cores in the stock cans. When you see how restrictive the OEM cores are to Steve's, there's no comparison.
As to not needing a tune, do a little research before deciding that. Every bike can benefit from a custom tune and even if you get a canned map from a pipe builder.
In my case, the map I got from Fullsac was a good starting point but wasn't perfect for my bike. Front cylinder was lean, rear was drowning. There was a vibration after installing the pipe/map from 1800-2800 that wasn't there before. Dyno showed why. Even if I couldn't feel something was off, unless you have it Dyno'd you wouldn't know. It's worth the $4-500 to have your bike's map dialed in.
Just my .02C.