In order to blend to the adjacing panels you are going to scuff them up good and first spray tour base on in thin coats over your new parts to just about cover, then on final three coats of base start with just a little blend in about five inches, then about ten then fade the last one out abut twenty if your car if faded or you are worried about match, when you are blending it take a bit of gun and flow control. Do not go off of just the look of the base alone as the ctear will bring out the true color. When you do clear, clear the facing panels all the way to a break. Takes some practice but is easier to do than sounds. When fading bring gun way back from surface to minimize the addition of color. You do not wand to change it completely but just give it the hue of the new color gradually.