If I replace my current amp with a new one, do i have to rewire?

[chawski 10+ year member]

4g wire should cost you about $2/ft (partsexpress.com). Maybe add another $10 on the fuse, terminals, etc. If you have access to a soldering iron, definately do it yourself. If not, with the cost of a soldering iron, youre better off just getting that set from crutchfield (which is still a bit on the pricey side, but if you dont have a soldering iron, i suppose youll still come out ahead just buying the kit from crutchfield)

 

[Fosgate 10+ year member]

You need a good soldering iron too and good solder. I tried to solder 4 gauge and it didn't work for shit. Not hot enough to melt enough solder and to keep it in a liquid state until it drains deep into the terminal. You're better off buying a kit pre-made unless you already have the materials. And besides i don't even solder connections anymore. Crimping gives a tight bond when using a vice.