I would go for the Titanium Silver one Shane in Pyrmont. You are getting more bang for your buck as well as a very clean and honest unmolested 335i with extremely low kms and a full BMW comprehensive service history. The Automatic in the E92 3 Series is a fantastic gearbox.
I will be honest with you Shane, that these days people aren't after Manual gearboxes anymore. If you were to sell the grey one in the future, it's going be an absolute nightmare trying to find someone who wants a 335i in Manual. It's quite a rare choice, i don't think I have ever seen a 335i in Manual. Think of it this way, your ordinary businessman will not buy a Manual 335i as an everyday car, it's just not suitable for that sort of market. I have noticed however that the particular car in interest has been for sale for quite some time. I honestly don't know why you haven't pulled the trigger on that Titanium Silver one. I just hope you make the right decision!
I would sign the deal straight away for the Silver one if it was me!