What is hte difference, or advantage/disadvantage to using the HKS grounding kit which connects all the cables to the negative battery terminal, as opposed to the insaneamine grounding kit which only has one cable connected to the negative termnal??

Heres the HKS kit

 

HKS uses 8 gauge wire
InSaNeAmine uses 4 gauge wire.

Arguably, there is enough direct contact with the battery ground with the single 4 gauge wire and subsequent connections to stabilize the ECU signals and achieve the desired results.
Why pay an extra $50 and be stuck with purple??

 

i like purple

 

can anyone give a little more info on the advantages/disadvantages when comparing the hks to insaneamine kit??

 

Probably wouldnt be a huge difference, since grounding kits offer minimal effects anyways (Not in anyway saying they are useless). I would say the only differences would be in price, color, etc. You could also brag that you have a HKS kit, while most people could only say they have a DIY kit!

 

thats one of my biggest reasons
and i thought Purple would be cool with my car color