Have a look at my CX7 thread. I have big gains with intake and intercooler and base map etune with the stock MPS turbo. Some minor exhaust work to come followed by a full tune. The stock downpipe flows quite well and an upgrade is not really required with the stock turbo.
There are a number of options for an tune. I went with Stratified. Their blog has a page on the upgrade path for our DISI motors.
Also check out the JBR wide path intakes like I used. They are one piece silicone TIP and SRI.
CX7 - The younger, taller and sexier replacement for the MPS6 and the first car designed around the MZR DISI
2007 CX7 2.3 DISI AWD Ice Blue | HID's | ETS TMIC | Cobb XLE BOV | CX9 20" wheels | 245/50/20 Scorpion STR's | CS HPFP | CX9 Brakes | Pedders Sports Ryders -40mm | CS Turbo | JBR 3.5" WPI | Cooling Mist WMI |Versatune