This has been my experience with the Unichip:
First of all, In GA we have 93 octane gas and I have been flashed since before I bought the Unichip. I bought it about two years ago. At first I just installed the Unichip without the EBC. With Map A, I immediately noticed that the car pulled much more smoothly through every gear. The famous hesitation was pretty much gone and the car seemed to have more power. The only other mod I had at the time was an Injen CAI. Map B did not really feel much different, so I mainly ran Map A to be safe because I heard on this forum that Map B has caused detonation at high RPM on flashed MSPs, as Sam stated above. I drove the car like this for about 7 months.
A few weeks before I got my exhaust, I installed the EBC. High boost setting spiked to about 13 psi and settled to 11. Although, this reading was from an Autometer guage so it could be a little off. I did not run high boost much at all because I had no intercooler or exhaust upgrades.
After installing Vibrant exhaust, I noticed that "stock" boost was 1 psi higher. At first, high boost setting seemed to be about the sam, but about the 3rd time of using it, it spiked to close to 15 psi. I never ran it again on high boost and eventually took the EBC out. I won't put it back in until I get a FMIC and am able to get retuned and have the ebc adjusted. Also, I may have been having wastgate issues during this time period and did not know it yet. That would probably explain why it seemed the same at first and then changed.
(During this time period I had some unrelated problems with my engine due a defective wrist-pin. Mazda techs found and identified the defect)
Now, I have replaced my wastegate actuator with a new one from ATP Turbo and I am seeing about an extra 1.5 lbs of boost, so the EBC definitely is not going in until the FMIC and retune/EBC adjustment.
Overall I am pretty happy with the results from the unichip, although I wish I would have better luck with the EBC. My car drives how I feel it should. Installation could not be much easier and I did not have to pay big $$ for a dyno-tune (yet, lol). If I ever decide to do some serious modding with a bigger turbo, etc., I'll probably go with a standalone. However, for moddest goals, the unichip is great.
The bottom line is, it kinda sucks we have to pay $400-$1000 to get our cars running like they should have from the factory. (drinks)