I'm not a fan of punching holes in the firewall or other sheet metal.
I as well have seen the effects of idiots cutting steering boots too, but like anything it can be done well and it can be done less than well...
FWIW, my boost gauge tube has been running thru my steering boot for 7-8 years now and its fine. As well, my water injection tube is thru it too, for 3-4 years now.
There is another stock grommet on the passenger side on a 1g, behind and below the battery, but on the passenger side.
As well, there is a tool that looks like a large hypodermic needle but bigger like a screwdriver size. Its designed to push thru rubber boots. Its hollow right thru, even the handle, so you push it thru the boot, and stuff the wire thru the middle of the tool, then pull the tool out. This works slick.