Speaking NOT from experience they are two different cars.
There are of course similarities (lightness, 'Britishness', etc) but I would say the Exige in particular is a far more focussed track beast that needs to be driven pretty hard to get satisfaction from.
I drove an S1 Elise briefly and loved it's simplicity but it was hard to get into, cramped, and just if I dare say it, a bit too kit car like for me (Awaits flaming); at the time I also owned a Westfield MegaBird so had some raw experience.
I'm rambling aimlessly, what I'm trying to say is that the Mog will be a different ownership experience and proposition whilst still giving you a taste of light sportscar feel and a raw un-coccooned driving experience.
I would also suggest your friendly local dealer ought to know more than most about these things
all I know about him is that he serves nice cakes
And of course welcome on board
