what kind of paint do you use to paint the interor such as the panel beind the ac/head unit?
also, ive seen people shorten their shifter by 2-3 inches. anyone have any advice or instruction as to how to do this?

Any auto paint can be used on the interior as long as it's on hard plastic, metal, or fiberglass. if its a rubber, leather or vinel you need to use a specific paint. dupllicolor makes both kinds of paint in a rattle can if you don't have a sprayer/compresser

First of all. DO NOT EVER CUT your shifter or shorten it. Just save up some money for a B&M short shifter. Also, if your gonna paint your interor accent pieces, get the Krylon Fusion paint or a paint meant to adhere to plastic. It will save you money in the long run and will look better as well. AGAIN, DONT SHORTEN YOUR SHIFTER BY CUTTING IT.