I've posted several times about Dr. Colorchip. I use it on my Imola Red M3. I assume it's a lot like langka, but I've never owned that. For sandblasting...I wouldn't consider another product....it works perfectly. For larger chips, you have to resist the urge to fill the whole chip in and layer the paint that comes with the kit. Apply it, let it sit a minute, then use the reducer to wipe off the surrounding area. Repeat several times (Spread out over days....not hours) until you've filled the chip. If done correctly, I can't even tell there was ever a chip there. If you do it incorrectly, the paint will not level out with the surrounding areas and wax will sit in there (and turn white) the next time you wax the car. If you forget to use the reducer on the supplied paint and it cures.....you might as well break out the sandpaper because that's the only way you'll fix it.