Why the high pitch sound when rpms raise?
 

Why is there a high pitch noise when the rpms raise? Is there a way to get rid of this?

how close is your wiring run to the factory wiring? are the RCAs run with the power wire?

The wires aren't that close the the factory wiring. The RCAs have their own way to the battery, they don't use the power wire.

it is a common myth that running RCA's next to power wire will cause alt whine. it won't.

what causes alt whine is a ground loop. resistance between the HU and amp grounds cause this. this is a common problem with Pioneer head units due to an internal failure and open connection. also, head unit grounding is important, i ground head units to the floor to minimize resistance.

you say you checked your ground, but show us a pic. i find people don't know what to look for or what a good ground actually is.