Unless you're very comfortable doing so, I wouldn't be turning up for a customer meeting in an Exige. Sends off the wrong impressions, sadly, and I get the feeling that impressions are very important to you. 350 you can laugh off as only a Nissan, Jag is still an old-man brand so that's okay, GTR looks like a box so again it's okay, but what is essentially (to most people) a racing car? I think you may not find impressions favourable.
Personally I'd split the fund, go buy an S2 Exige and something to trot around to offices in.