No need - it fits fine, although if you have it in a case you will have to either remove it or use an extension lead, putting the iPod on the shelf next to iPod cradle in the glove box.
One thing that's worth baring in mind though, the iPod functionality is limited to say the least with a maximum of 6 playlists and no track read out (basically the interface tricks the RNS-E into seeing the iPod as a CD changer - 6 playlists = 6 CDs). To be honest, I've never used the iPod interface myself, instead I bought a 32GB SDHC card from maplin for about £30 and converted all my tracks from AAC to MP3 using Foobar with the Lame MP3 encoder, which is freeware available for download on the internet. This way you can organise your songs into as many folders and subfolders of Artist and Album as you can probably fit on the card (so far I've got 220 folders with 2124 songs and no problems) and the Lame encoder is so good that if you use a high bitrate you can't really tell that it's been compressed.