I know I'm a few years too late, but if there's still interest in this epic car, converting the HD image online to a vector format and scaling it down that way may help with the issue mentioned. You can easily grab the HD logo through Google. When a friend created it years ago, it was done in vector format originally, so it should convert back fairly easily.

@Mickael Blake
Thank you very much for your response. i think it would help.

Well all I can suggest you is manually deleting the bad and weird looking pixels when you make it smaller ^^

@Mickael Blake
I did used high quality sticker/ logo. But when i make the logo smaller, it will pixelated and blurry in the final product. High resolution won't solve the problem :(
Any ideas?