I was wondering if i can use 8k on lo beam and install 10k on high beam

 

Yes...
High Beam requires Kit and Yes.

 

I was looking to install 8k on low beams as well, but I can't find a oem bulb with this specification, only aftermarket bulbs, I hear these aftermarket bulbs are not sae/dot approved and wont pass inspection. Anyone know if this is true, or where/what brand HID am I to use to for 8k and dot approved?

 

if you go hid make sure you get projectors or eyelids. with the stock reflectors hid's tend to blind the crap out of people. and with our cars so low 90% of the time an eyelid will help