Mine's very similar to RBH. The little blip or hang at 12-1300 rpm is a bit random (not exactly the same every time), I've always considered it normal. I think it's just a by-product of the ECU tune. I have a KoldFire tune, but I think it is pretty much the same with the stock S240 tune (though idle is more steady on the KF tune). FWIW, I did have an intermittent stalling and "lean bank 1" issue when my car was new, the dealer replaced the SC/intake manifold gasket on warranty, and it's been fine since.
'08 Arctic Silver Exige S240