Eurocode can glad your ECU for you. You either send it to them or just drive there. After that, the programming can be modified with what REVO calls a serial port switch. They can either tune it just through your ECU or they can go through the OBD2 connection. And yes, I did drain my fluids, all except my brakes. The power steering isn't needed but I was installing a cooler for it at the same time. Lastly, I'm running the test pipe that comes with the kit the offer. It has been great so far. Well, except or smog regulations.. But apart from the kit, you'll want to get a blow off valve. You'll be pushing too much boost and blow out your stock divertor valve like I did. Also, I'd recommend making a boost leak checking tool for your install. I was suffering with A LOT of boost leak for a long time. Just save yourself the hassle and make one right away.

Already running a forge diverter valve so not an issue. The wastegate should handle the overflow of boost. Also running an Evo Raceworks Comp FMIC, so I am set on keeping cool.
Are you sea level or altitude. I am in Denver and was told this kit starts spooling at over 3k. Not attractive.
I am curious when you are starting to see the turbo spool, what your altitude is.

I am at sea level. I would say it starts spooling just a little bit after 3k and you hit full boost at about 3800. What kind of driving will you be doing with it? I really don't notice the turbo lag at all when I'm ripping through gears.

Well after talking to ATP, and I spoke to two of the race engineere, they both stated the GTRS is their most streetable solution and spools 5-600 RPM below the GT71R turbo. They stated best setup is this:
GTRS Turbo
Bosh 44lb injectors
Bosh three electrode spark plugs
Downpipe/High-flow Cat if you have severe emissions
3" Catback.
3" Turbo Inlet Hose
Stage 3 ECU with a tune.

I was surprised that they told me a high flow manifold is not needed and has no effect They emphasized the downpipe and cat-back for fast spooling and tons of torque.

Just glad I spoke to them before going with Eurocode. Their tech told me totally opposite numbers then ATP's engineers.