I can install and paint match your body kit for $800 or so depending on initial fitment of the kit and how well you want it to fit.

As far as a color change goes, well, are you wanting to go into door jambs, under the hatch and the hatch jamb area, under the hood, the engine bay, etc???

Including the body kit I would do a basic outside respray in white for $1,600 if there is no major bodywork needed.

Here is the link to a G35 I just recently did that had a Kenstyle kit installed: https://www.tamparacing.com/forums/paint-body-detailing/664818-kenstyle-kitted-g35-i-recently-did.html