I am liking what you are saying
I am looking into(not real intently yet as to many other projects, etc, right now) for the least costly yet very effective self tuning way of setting up our turbo system, having a built in wideband is one great way to attain these goals!!!
I have had alot of dyno tuning done with systems I was not allowed to have the programs for, not going that route again and we know it is a way to establish a base line but is not entirely transferable to actually driving the vehicle in many situations.
I do like piggy back system since it allows the stock ECU to manage the more mundain daily driver issues. Reflashed ECU's would be cool as well and of course changing rev limits, where applicable and deleting speed govenors are something cool to address.
If I could get a decent reflash to fix a few things and run a good fuel sytem, timing is also really nice to tune, that would be my idea of the ideal way to boost a modern vehicle.
I like the Unichip overall, if only I could have access to the software, I would probably go that route, Jack was going to do a custom dual map setup on my Turbo Matrix once the engine was built, 1100 mile trailer trip to get it done. Now that we will be within 30 miles or so from them, maybe we will end up with one again
The last plan was to have a high and low boost setup that controlled timing, fuel, boost onset and offset at super high RPM, 8,600 redline, delete the speed govenor(the last two hard ware mods to the stock ECU), a GT25/40 turbo, totally built engine, this project was well on the way when I sold off everything to help my disabled buddy out.
The plan was this: 10:1 compresion with forged pistons and billet rods, .300 longer than stock, Darton sleaves(had them custom made). fully ported and polished, flow benched head, custom cams(if needed), knife edged, lightened and rebalanced crank, 5 angle intake, radius exhuast valve job, etc, etc.
This was based on a lessor built but very well put together engine that put out over 300 WHP and over 280 ft lbs from a 1.98 liter 1ZZ. Stock head and 7k redline, 12PSI, 91 Ocatane.
1) Low boost, 12PSI, 300+WHP, nearly 300 ft lbs, 91 octane. Unichiped tuned to control the onset of boost for a smooth bottom end to avoid excessive wheel spin out of corners then drop of boost at super high RPMS to protect the engine and allow less shifting between corners. A very wide powerband of approx 6k RPM

The unichip would also control the Aquamist Met/water injection I was already using, also timing and fuel.
2) Remote on steering wheel, only used when race gas in the tank, once hooked up well in a drag or out of a corner, remaps the fuel, timing, boost to come on immediately and stay on to redline, Aquamist, etc, etc. 17PSI, expected well over 400WHP and nearly that much torque.
Though this sounds a bit fare fetched, believe me, several very sharp and experienced minds were involved in this plan and all the hard parts were on track to be custom built, alot of partial and some full sponsorship, all well known and respected parties except the main engine idea guy I learned what could be done with a 1ZZ from, not so well known Japanese engine guru.
OK, now we have a tC instead and the goal is a daily driver 300WHP reliable machine which from all I have read is really easy to do and far more cost effective
Rick