The guys are correct. Drill the box wing side and add a K&N.
By the way the 9A is actually KE-Motronic, not k-jet. There are some minor differences, like the amount of fuel carried to the injectors is ECU controlled, plus it has lambda control, and knock sensors.
Are you running a 9A on k-jet? that is the usual mod for mk2 golfs with KR engine.