Visible differences between 407 SR 1.8 and ST 1.8

Hi there,

I'm in the market soon for a used Peugeot 407 saloon and have chosen
to go for the 2005 model of either the SR 1.8 saloon, or the ST 1.8
saloon

I've done my research and know that there is a reasonable difference
in price (at least here in Ireland) between the two models and a
difference in some extras.

What I'd like to know, is how is it possible to tell which model I'm
looking at? Both the SR and ST seem to be exactly the same from the
outside (I've only seen pictures), and I'd like to be prepared before
I go speaking with some canny salesmen

Any help appreciated,
Martin.