I used the unichip for a while when i had heads and cams springs and retainers, and it worked very well for that application. But after the full rebuild we found the car was difficult to tune. Also it runs lean up high (we were not able to add more fuel) and rich down low...definitly not perfect, and it will never get there with the Uni. But for mild N/A mods like heads cams etc, it is really great in my opinion. But it depends how far you go...a piggy back only goes so far. Unichip was surprised we even got the car to run reliably with the Uni with the motor i have, they reccomended I switched to stand alone.
But my LINK did arrive last week and we plan on tuning the car after next week. We figure the link will benefit the car very very much considering its far from perfect right now and we plan on seeing mid to high 13 second passes (fingers tightly crossed!).
I hope this helped a bit. Good Luck.