post all your gimp questions in here instead of posting 50 million help me's....
okay heres the deal...in the knock off photoshop and gimp the painting systems are less sensitive, personally i think gimps is better tho....you can use two methods to paint a car....hue saturation, and color balance...colorize works too but is too saturating to do anything with.....
first off, when painting, make a new layer so you can go back to the original if you screw up and fix something...and you can play around with the layer types to creat cool paint jobs....
then select the area you wanna paint with the lasso tool
when you use the hue/saturation try and lower the sat sometimes...too high sat will pixelate it...but also make the colors pop more sometimes..also make sure to use the 1600x1200 pictures so its harder to pixelize them, then do everything normal and resize to 800x 600....f
or color balancing, try desaturating first, then colorbalancing...don't use colorize tho...after color balancing you can go back and use hue/sat to get what you want, but sometimes you just can't make a certain pain job from a certain paint job
then you can use levels to darken, lighten, and make flat paint jobs....and after awhile of playing around sometimes be able to chrome bumpers and things through use of layers
lowering specifialy for gimp will be posted soon along with other gimp specifics