I can't comment on GeForce as I haven't seen/driven their work personally. If you're planning a more hardcore engine, I'd save the entire ecu exercise for then (saves retuning costs). No need for a spare motor, just buy the internal hardware beforehand. The majority of my car's downtime was due to awaiting the arrival of parts.
As far as exhaust goes, I'd just grab a nice Jap exhaust (Phoenix Power etc) from Dylan. Would be cheaper than HiTech & "jdm sexy yo". As for the dump pipe, there's actually a significant improvement by changing it, so I'd still do that & sell it down the track if need be. Just make sure you brace any aftermarket downpipe as even the best have a tendancy to crack.
No complaints re the intercooler choice either. W2A is the way to go, no sacrifices & I've been running a W2A for years now without any negative side effects. Mine's never heatsoaked.
You can comfortably run about 16psi with the stock ecu/ct20b. Can probably go to 18 as long as it's not a hot day, but I'd want to put on a seat of headphones to verify it's not detonating. The issue at that boost with the stock ecu isn't really fuel related, it's ignition timing which gets aggressive from memory. The CT20B turns more into a hairdryer at close to 20psi & beyond. I used to & preset 16 & 18psi on my ebc when I ran the stock ecu & Blitz K1. Crazy ba$tards like Tristan in WA have run a GT30 @ 20psi on the stock ecu......hahaha Good old days.
Those mods are already enough to crack into the 12's from personal experience. Not too shabby.