The Dinan CAI produces a hissing sound at low RPMs which I find cool and some others find annoying.
I have Dinan Stage I, II, III, with CAI and Throttle Body. Before the UUC exhaust, my best run was 6.2 seconds, which is an improvement over the listed 7.1 seconds (steptronic). Note, however that I never did a run when the car was stock. Never checked my 1/4 mile times since I'm not that big into straight line acceleration.
I've got a 330 and short of a supercharger, the engine mods available don't make a whole lot of difference. For differences you will notice, look into upgrading your suspension.