So?
*Oh, muß dann noch "signifikant" gemacht werden; aber ich denke das Prinzip ist klar.*
![alt text][1]
\documentclass{article}
\usepackage{selinput}
\SelectInputMappings{adieresis={ä}, germandbls={ß}}
\usepackage[ngerman]{babel}
\usepackage{siunitx}
\usepackage{xcolor}
\pagecolor{lightgray!10}
\newcommand{\SIxx}[3][yellow]{\colorbox{#1}{#2}\,\SI{}{#3}}
\usepackage{contour}
\newcommand{\SIx}[3][red]{\contour{#1}{#2}\,\SI{}{#3}}
%=========
\begin{document}
%=========
{\Huge Alt:}
\[ \SI{3.8320}{\gram} = \SI{0.0038320}{\kilo\gram} \]
\contour[20]{blue}{\Huge Neu 1:}
\[ \SIx{3.8320}{\gram} = \SIx{0.0038320}{\kilo\gram} \]
\[ \SIx{3.8320}{\gram} = \SIx[green]{0.0038320}{\kilo\gram} \]
\[ \SIx[purple]{3.8320}{\gram} = \SIx[yellow]{0.0038320}{\kilo\gram} \]
\colorbox{cyan}{\Huge Neu 2:}
\[ \SIxx{3.8320}{\gram} = \SIxx{0.0038320}{\kilo\gram} \]
\[ \SIxx{3.8320}{\gram} = \SIxx[green]{0.0038320}{\kilo\gram} \]
\[ \SIxx[purple]{3.8320}{\gram} = \SIxx[yellow]{0.0038320}{\kilo\gram} \]
%=========
\end{document}
%=========
[1]: http://texwelt.de/wissen/upfiles/Namenlos-11e4a_1.png
