Awesome pics and great write-up, Frissen,
As you can see by my signature, I too have tweaked my 996TT using the EVO/GIAC package. I got a 2005 996TSCab last summer and added the EVO/GIAC mods over the winter-EVO diverter valves, headers, Venturi flow intake, silicone hoses, GIAC chip for the stage 4/600 package, with a Sachs GT-1 level 2 street clutch, and Milltek TT/GT-2 exhaust. I haven't dynoed it or timed any runs with a GPS (too busy this summer with non-car stuff), but it's VERY FAST, no matter what the HP and torque numbers are-and it runs smoothly, driveable as a daily driver, but ferocious when I want it to be. I AM keeping it and I AM tempted to tune it up to the 700-800HP range, but I'll await my 997TT (I'm leaning toward getting a coupe version-either TT or TTS and tune with a bigger VTG), and await the end of the warranty before modding the engine-2008 or so. I would then need to upgrade the brakes and suspension-this winter I'll probably just change it from stock to the X73 option, and add some CF pieces to the interior. BUT, no exterior bling, the skin stays stock.
Plus I have my Noble M400 to "fiddle" with.
I've just finished the run-in on that car, and this winter I'll tune that one up with perhaps a turbo upgrade from stock Garrett T28R's to T28RS's, upgrade the oil cooler, amongst other things. In stock form, though that car is pretty quick too.
Good to see some more Porsche tuning south of our border. And more 911Turbo nuts like me extracting the potential from these cars in a civilized manner.