Sounds like you will be the expert on what running a turbo capri without a muffler is like. Maybe the turbo needs a little back pressure to spin up properly, you still getting good indicated boost at the gage?
On a personal note, PUT THE MUFFLER BACK ON SO MY HEARING WON"T BE DAMAGED IF I RIDE UP BESIDE YOU.
Just a pet peave of mine, in Florida we have a no-muffler-ok law for motorcycles, and gets pretty noisy at times. Of course, we also have a no helmet law, so the number of bikers is thinning out due to head injuries...