Battery Relocation Question

[mmtmatrix]

Hello everyone, sorry for the battery questions but searched and couldn't quite find what I was looking for.

Anyway, am in the process of doing a battery relocation on my S13 hatch. Went to get a battery distribution block from an audio electronics store where a friend works and ended up buying a monster kit because he was able to give me a discount.

My questions are; This kit comes with 22 feet of 4 gage wire (for wiring an amp), I was planning on using this for my power cable, some people say 4 gage is fine, others say that it will be too small? Thoughts?

For those running batteries in their trunks, where/how did you route the power cable? I am leery about going under the car due to damage from road conditions, but also am unsure about through car due to heat and EM damage (possible to ecu?). What have others done?

Also, it came with a fuse, should I use this?

Thanks for all the help,
mmtmatrix