GSXR 600 1998 Balance pipe

Hi Guys

I have a new dual O2 sensor setup by Innovate ,

id like to put on my Gixxer to help me tune the carbs to the correct AFR,

Ive planned to put them in the 4 into 2 pipe section (see Pic),so 1 sensor will read cylinders 1&2 and 3&4 but , Innovate say I cant run the o2 sensors after the balance pipe that runs between cylinders 2 & 3 as readings will be skewed,
The pic shows location of proposed install

so,

1.Why is that balance pipe there ? between 2 & 3
2. can i delete it ?

View attachment 301106