6.5" component can fit myvi rear speaker hole?????

Yup.. Can fit in nicely.. Use baffle for good result and check whether u need to cut the door trim at the speaker area (round shape) if ur speaker is big.. Hehehe

yes can fit haha

bro i got something wanna ask u..after i install preamp 5 band and 4channel hantam component i felt my woofer bass sometime loud sometime normal..>.< what is the problem

Maybe not enough power? Do u have capacitor for the sub?

no worr..>.<..LOL or issit the preamp setting not nice??

Might be not enough power and your alternator cannot keep up
And actually cheap pre amp also no good more distortion

Comfirm is not enuf power?..>.<

Your subwoofer 900rms + 4 channel I think stock myvi alternator not enough power

if lik tis need how much to change?..>.<

and wat is the problem for my component tweeter..even i 0 volume aso got bsszzz sound..>.<

That is interference sound might be the rca is near power cable or got grounding problem
This is just prediction
Check if unplug rca still got buzzing noise or not