QTP exhaust cutout mod

Like my W222 come with 2.5" pipe so I order a pair of 2.5" exhaust cutout:
If thats your car your installer picked the perfect spot and tacking the end to the pipe was just perfect.
I also wonder how do you tune for this as you arr eliminating back pressure. I get the computer can compensate to some degree but without a tune I would be curious to know how the car runs when open and excelerating hard?






