How did you remove the db killer? I always hated cutting and drilling expensive parts. That one doesn't look like it's easy to access?
For Akro's, I think the difficulty depends on your particular exhaust. The way I did mine:
1. There is a gap (red) between the metal and carbon fiber. If you shine a light down the gap then follow it around you should be able to see where the bolt is assuming your exhaust's gap goes all the way around.
2. If you can see the bolt you should also be able to identify the hole outline (blue) for it.
3. Once you know where both are just take the appropriate measurements then drill in from the carbon fiber (yellow) side. I was able to reach it using a 3/8 drill bit.
4. The bolt is on TIGHT so a torque wrench may be necessary. Just be careful not to strip it - I almost did.
5. Once the bolt is removed I used a wrench to grab the 2 center exhaust metals and wiggle the db killer out.
6. Afterwards, I used rubber grommets to cover the drill and bolt holes.
Hope that helps!