I have some spare 4 Awg OFC wiring which isn't enough to utilize for a amplifier wiring run but more than enough to do a complete BIG3 wiring kit. For anyone who's interested in it can let me know and I'll make the wiring kit for you on order according to the lengths you mention
This is what it will consists of.
1) Alpine 20 mm² (4 AWG) Main power wire from Alternator to Battery (+) with 200AMP Inline fuse holder. Will come in two pieces since the fuse holder will be placed near the battery. If wanted, the fuseholder can be skipped all together. The length of this wire generally is 1.5-2m
2) Alpine 20mm² (4 AWG) Ground wire from battery (-) to Engine. Total length can be from 0.5-1.5m
3) Alpine 20mm² (4 AWG) Ground Wire from battery (-) to Chassis. Total length can be 0.5-1m
All the wires can be covered in Braided sleeving or flex tubing and properly crimped with color coded heatshrinks.
For anyone who's not even running a sound setup, this is a great way to upgrade the wiring in your engine bay. The benefits are loads with no down sides of a Big3 upgrade
Here are a few examples of the Big3/4 kits i've made and running currently