I have used this answer to include two pdfs in landscape format. It works good for one page but not for two. This is my example:
\documentclass[twoside]{scrartcl}
\usepackage{fancyhdr}
\usepackage{lipsum}
\begin{document}
\pagestyle{fancy}
Some text...
\newpage
\paperwidth=\pdfpageheight
\paperheight=\pdfpagewidth
\pdfpageheight=\paperheight
\pdfpagewidth=\paperwidth
\headwidth=\textheight
\section{New Section}
\begingroup
\vsize=\textwidth
\hsize=\textheight
\begin{center}
\includegraphics[width=1.3\textwidth,page=1]{bla.pdf}
\end{center}
\newpage
\begin{center}
\includegraphics[width=1.3\textwidth,page=2]{bla.pdf}
\end{center}
\endgroup
\newpage
\paperwidth=\pdfpageheight
\paperheight=\pdfpagewidth
\pdfpageheight=\paperheight
\pdfpagewidth=\paperwidth
\headwidth=\textwidth
Some Text...
\end{document}
My problem is that I'm using a twosided documentclass and the header is shifted to the left on even numbered pages. In addition I don't get pagenumbers in the footer on landscape pages.

geometry-package for this? – Runar Dec 28 '15 at 12:21fancyhdrwithscrartcl, you get respective warnings in the log-file. – Johannes_B Dec 28 '15 at 12:31