is UTTG good for Matte stripes

I was wondering does it do a good job on Matte black car Stripes..was thinking of adding some to my mustang..and my buddy has them stock on his 2010 Camaro SS and He got a bottle of UTTG as well in my order. nothing seems to ever make his stripes look nice and even and black..no matter what used on them it seems they look like crap in like an hour or after first time getting wet

i guess see how well it works..that order of my 2 bottles of UTTG i am guessing wont be here till monday