Unichip sucks, it's close to impossible to find a place to tune the car properly and it's expensive as balls, it's just not worth it, my brother had it on his car, and I sold it and switched to the ssafc which I have on my car, the ssafc does have some slight problems.. well 1 problem which is that I have noticed that eventually it seems the comp. will tend to learn around it slightly because the fuel ratios will increase (closer to 10 or lower I mean) after a time, it lasted almost a year last time, but then all of a sudden when I went of vacation and it sat for a week (I had just re-loaded the map before leaving) the car went back to crazy rich and stuff, so I just re-loaded to map and it was great again, but kind of strange..
I guess that the unichip would have that problem anyways also, and the only way around that is with a full standalone... but until then, it's great ..