Wiring through the cab

[Z71Silverado98]

i just recieved the b&m shiftplus unit and need to send the wiring from the cab to under the hood, but i am a little concerned about just drilling into the firewall. help would be appricaited.

[JB]

Dont drill thru the firewall, just run it thru near where the steering comes thru the firewall, theres allready a grommet for the wiring harness.