drilling is not required on a 5G civic. If you are using oem sway bars you will need lower control arms from a 3G teg or a 5G 4 door EX. The have the correct lcas for a sway bar. Do not drill the lca of the stock civic lca they are too thin. As far as the subframe goes clean it off and you will notice holes there. These holes are for the step bracket that the d bracket bolts too. As far as the subframe tearing a 21 mm bar is big enough to rip rip the subframe. Ive got an itr rear sway on my EG8 and its ripped out. I took it to Tito Chasis works in Ocala he builds mostly tube frame chasiss but was able to fix it and makesit stronger than stock. If you are going with the ST sway bars you dont need to drill they give a kit that bolts over the lca so you dont need to drill. If you are refering to the front sway bar again you dont need to dril just use hte lca from a a 5g civic with a fron sway bar or the 3g teg the holes for the front subframe mounts are already there. Keep your drill on the workbench cause you wont need it.
Robster