power wire from battery into the car

I've read loads off posts all saying go through the grommet for my power wire for my amp.
I've tried the grommet but there's so many wires through it already that I can't get anything through there
I've tried looking for the grommet that is to the left of the heater pipes but can only find a small one above them slightly to the left can't find it on the iniside there's a plastic case off some sort in the area so I assume that's in the way.
I'm running knuconceptz 4 gauge wire so I'm thinking the best way is going to be to drill through the bulkhead but I don't want to hit anything if anyone has done this can you please send me a picture of where to drill or if there is another grommet not in use
Forgot to say it's a 2007 197 now sure if there's a diffrence between the 197 and 200 on this

Thanks
Jack
 
I only did this on my non sport but i assume it's the same...

I pierced a seperate hole in the grommet behind the glove box with a screwdriver and sent some firmer wire through (i used a piece of twin & earth cause its nice and tuff) then tape the amp wire to that & pull it all through inside, this may take a few attempts but it works- just dont pierce anywhere near the loom. Oh and dont use a drill lol