I have done big 3 and bigger battery upgrade. Now thinking to add capacitors.

my current system:
alpine 9887
H701 DSP
Focal FP1.800 mono
Focal FP2.150 2ch amp
PhD 4060 4ch
Boston SL60 set (active)
midrange (buying soon, not yet decide which brand to use)
Focal 30A1 sub
my power cable to trunk is 4 gauge. Since Im not going for competition, 4 gauge should be enough for my usage.

for capacitors, I heard those cheaper one are from same manufacturer from china (streetwire, efx etc). So I narrow down my choices to 3 brands:

1) Helix
2) Mundorf
3) Rockford

Helix and mundorf are basically the same level for me. But for rockford, Im considering the RFC10HB, which is a 10farad hybrid cap. A lot of positive reviews on the rockford cap. But the main problem is, if I get the rockford, I wont be able to connect it to all amps within power cable of 45cm. And with the same budget, I can get 2 or 3 mundorf or helix 1farad cap.

So my question is,
-should I get 2 or 3 mundorf caps, place it right beside aech amps OR get 1 unit of rockford cap, hook up all amps to it?
-will a good quality cap improve sound quality? will I get cleaner sound when I play music loud?
-should I invest on a voltage stabilizer instead of caps?
-will the 10 farad help when Im not using it for SPL?

Ur comments and suggestion will be appreciated. Thanks

oh really? what is the brand of capacitor u using? I dont dare to DIY caps, I scare my car kaa boommmm

I considered before to upgrade my cable to 0 gauge, but my friend (technician) told me, for the volume I play, 4 gauge is more than enough. The main reason I used 4 gauge is because that was what my sold system use. and since my friend told me so, so I dint upgrade. really should I upgrade to 2 gauge? not much to do that also, will upgrade if necessary. btw what dry cell do u recommend? size and brand? I never thought of having second battery in my trunk even though I seen people did this before. Cause my car is not for competition, I thought that wont be necessary. Same goes to the alternator. and my car's engine is still under warranty, dont dare to change alternator

any other sifu think I should use 2 gauge or above?

if 1 amp got 2x30A, mean 60 or 30? lol

no more electrical warranty but engine warranty still have 2 years to go. Change alternator wont affect engine warranty ah?

yea... I have been claiming warranty twice for my turbo. so far no prob