I know that it is recommended to run the power & RCA cables seperate but does this also apply to speaker cabling or doesn't it matter with the speakers?

What about running power/RCA/speaker cables with existing vehicle looms?

I think RCA's or anything that goes to an amp is supposed to be kept away from everything, as the magnetic fields from other wires carrying enough power create tiny voltages in the signal wires, which the amplifier sees as part of the sound signal and amplifies with the sound that you actually want to hear. I wouldn't go running a monster power cable for a huge boot install right next to any sensitive electronics/computers in your car though, but I don't see much harm in it going next to the power wires for your windows or electric seats.

speakers wires can have noise induction from being placed close to electrical equipment, while its commonly accepted that the voltage is too high through speaker wires to worry about line noise, I was shocked to find that the line noise in my system still existed after disconnected the speaker wires from the amplifier all together.

Hmmm ok so power, RCA's & speaker cabling should be run seperate from each other & also away from existing vehicle cabling to be safe?

generally run power and trigger on one side, and rca's with speaker wire on the other side.
that said ive seen many installs come into work from professional installs that have run the power and rcas on the same side and have no issue.

Ok thanks for that. I'm guessing the so called pros run twisted pair rca's so less likely to pickup any unwanted noise.

not in all cases lol but in most yes