Actually your car with a race muffler is pretty much stock since there is nearly 0 hp gain from that but the 911 removing the cats is a massive horsepower gain especially on a turbocharged car so that is very impressive
Guys the porshe owner modded his car, tune and increase boost to 1.1 bar + remove the cats.
Also i have order ess tune and soon i will get the cable to flash it. I already installed the following: bmc filters , rpi air scoop and power agency pulley. We will give it another try after both cars now modded.
I am out of the country probably we will do the race after 1 week